WO2005026209A2 - Monoclonal antibodies against hmgb1 - Google Patents

Abstract

In various embodiments, the present invention is drawn to antibodies or antigen-binding fragments thereof that bind to a vertebrate high mobility group box (HMGB) polypeptide, methods of detecting and/or identifying an agent that binds to an HMGB polypeptide, methods of treating a condition in a subject characterized by activation of an inflammatory cytokine cascade and methods of detecting an HMGB polypeptide in a sample.

Description

MONOCLONAL ANTIBODIES AGATNST HMGB1

RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 60/502,568, filed September 11, 2003. The entire teachings of the above application are incorporated herein by reference.

BACKGROUND OF THE INVENTION flaiimiation is often induced by proinflammatory cytokines, such as tumor necrosis factor (TNF), interleu in (JL)-\ , E -lβ, IL-6, acrophage migration inhibitory factor (MIF), and other compounds. These promflammatory cytokines are produced by several different cell types, most importantly immune cells (for example, monocytes, macrophages and neurrophils), but also non-immune cells such as fibroblasts, osteoblasts, smooth muscle cells, epithelial cells, and neurons. These proinflammatory cytokines contribute to various disorders during the early stages of an inflammatory cytokine cascade. The early promflammatory cytokines (e.g., TNF, IL-1, etc.) mediate inflammation_^and induce the late release of high mobility group box 1 (HMGB1; also known as HMG-1 and HMG1), a protein that accumulates in serum and mediates delayed lethality and further induction of early proinflammatory cytokines. HMGBT was first identified as the founding member of a family of DNA-binding- proteins, termed high mobility group box (HMGB) proteins, which are critical for DNA structure and stability. It was identified as a ubiquitously expressed nuclear protein that binds double-stranded DNA without sequence specificity. The HMGB1 molecule has three domains: two DNA binding motifs termed HMGB A and HMGB B boxes, and an acidic carboxyl terminus. The two HMGB boxes are highly conserved 80 amino acid, L-shaped domains. HMG boxes are also expressed in other transcription factors including the RNA polymerase I transcription factor human upstream-binding factor and lymphoid-speciflc factor. Recent evidence has implicated HMG1 as a cytokine mediator of delayed lethality in endotoxemia (Andersson, U., et al, J. Exp. Med. 192(4):565-510 (2000)). That work demonstrated that bacterial endotoxin (lipopolysaccharide (LPS)) activates monocytes/macrophages to release HMG1 as a late response to activation, resulting in elevated serum HMGl levels that are toxic. Antibodies against HMGl prevent lethality of endotoxin even when antibody administration is delayed until after the early cytokine response. Like other proinflammatory cytokines, HMGl is a potent activator of monocytes. Intratracheal application of HMGl causes acute lung injury, and anti-HMGl antibodies protect against endotoxin-induced lung edema (Abraham, E., et al, J. Immunol. 265:2950-2954 (2000)). Serum HMGl levels are elevated in critically ill patients with sepsis or hemorrhagic shock, and levels are significantly higher in non-survivors as compared to survivors. HMGl has also been implicated as a ligand for RAGE, a multi-ligand receptor of the immunoglobulin superfamily. RAGE is expressed on endothelial cells, smooth muscle cells, monocytes, and nerves, and ligand interaction transduces signals through MAP kinase, P21 ras, and NF-kB. The delayed kinetics of HMGl appearance during endotoxemia makes it a potentially good therapeutic target, but little is known about the molecular basis of HMGl signaling and toxicity. Therefore, given the importance of HMGB proteins in mediating inflammation, it would be useful to identify antibodies that bind HMGB for diagnostic and therapeutic purposes.

SUMMARY OF THE INVENTION In various embodiments, the present invention is drawn to antibodies or antigen-binding fragments thereof that bind to a vertebrate high mobility group box

(HMGB) polypeptide, methods of detecting and/or identifying an agent that binds to an HMGB polypeptide, methods of treating a condition in a subject characterized by activation of an inflammatory cytokine cascade and methods of detecting an HMGB polypeptide in a sample. In one embodiment, the invention is an antibody or antigen-binding fragment thereof that specifically binds to a vertebrate HMGB A box but does not specifically bind to non-A box epitopes of HMGB, wherein the antibody or antigen-binding fragment inhibits release of a proinflammatory cytokine from a vertebrate cell treated with an HMGB protein. In certain embodiments, the invention is an antibody produced by murine hybridoma 6E6 HMGBl mAb, murine hybridoma 6H9 HMGBl mAb, murine hybridoma 2G7 HMGBl mAb, murine hybridoma 2E11 HMGBl mAb, or murine hybridoma 10D4 HMGBl mAb. In other embodiments, the invention is an antibody or antigen-binding fragment thereof, wherein the binding of the antibody or antigen- binding fragment to a vertebrate HMGB polypeptide can be inhibited by 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2E11 HMGBl mAb and/or 10D4 HMGB 1 mAb. In still other embodiments, the invention is an antibody or antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment has the epitopic specificity of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2E11 HMGBl mAb and/or 10D4 HMGBl mAb. In certain embodiments, the invention is an antibody or antigen-binding fragment that binds to a peptide consisting of amino acid residues 46 to 63 of SEQ ID NO:l, amino acid residues 61 to 78 of SEQ ID NO:l and/or amino acid residues 151 to 168 of SEQ ID NO:l. In one embodiment, the invention is an antibody or antigen-binding fragment, wherein the binding of the antibody or antigen-binding fragment to a peptide consisting of amino acid residues 46 to 63 of SEQ ID NO:l, can be inhibited by 2G7 HMGBl mAb. In another embodiment, the invention is an antibody or antigen-binding fragment, wherein the binding of the antibody or antigen-binding fragment to a peptide consisting of amino acid residues 61 to 78 of SEQ ID NO:l, can be inhibited by 6E6 HMGBl mAb and/or 6H9 HMGBl mAb. In yet another embodiment, the invention is an antibody or antigen-binding fragment, wherein the binding of the antibody or antigen-binding fragment to a peptide consisting of amino acid residues 151 to 168 of SEQ ID NO:l, can be inhibited by 2E11 HMGBl mAb. In certain embodiments, the invention is an antibody or antigen-binding fragment that comprises the light chain CDRs (CDR1, CDR2 and CDR3) and the heavy chain CDRs (CDR1 , CDR2 and CDR3) of an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and 2G7 HMGBl mAb. hi other embodiments, the invention is murine hybridoma 6E6 HMGBl mAb, murine hybridoma 6H9 HMGBl mAb, murine hybridoma 2G7 HMGBl mAb, murine hybridoma 2E11 HMGB 1 mAb or murine hybridoma 10D4 HMGB 1 mAb. I another embodiment, the invention is an isolated cell that produces an antibody or antigen-binding fragment that specifically binds to a vertebrate HMGB A box but does not specifically bind to non-A box epitopes of HMGB. In other embodiments, the invention is an isolated cell that produces 6E6 HMGBl mAb, 6H9 HMGB 1 mAb, 2G7 HMGB 1 mAb, 2E11 HMGB 1 mAb or 10D4 HMGB 1 mAb. In still other embodiments, the invention is an isolated cell that produces an antibody or antigen-binding fragment thereof, wherein the binding of the antibody or antigen- binding fragment to a vertebrate HMGB polypeptide can be inhibited by 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2E11 HMGBl mAb and/or 10D4 HMGBl mAb. In still other embodiments, the invention is an isolated cell that produces an antibody or antigen-binding fragment that has the epitopic specificity of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2E11 HMGBl mAb and/or 10D4 HMGBl mAb. In other embodiments, the invention is a composition that comprises an antibody or antigen-binding fragment of the invention and a pharmaceutically- acceptable excipient. In another embodiment, the invention is a method of detecting and/or identifying an agent that binds to a vertebrate HMGB polypeptide comprising combining an antibody or antigen-binding fragment of the invention, a test agent and a composition comprising a vertebrate HMGB polypeptide. In the method, the formation of a complex between the antibody or antigen-binding fragment and the HMGB polypeptide is detected or measured and a decrease in complex formation, as compared to a suitable control, indicates that the test agent binds to the HMGB polypeptide. In another embodiment, the invention is a method of treating a condition in a subject characterized by activation of an inflammatory cytokine cascade comprising administering to the subject an antibody or antigen-binding fragment of the invention.

In certain embodiments, the condition is sepsis, arthritis or lupus. In another embodiment, the invention is a method of detecting a vertebrate HMGB polypeptide in a sample. In the method, a sample is contacted with an antibody or antigen-binding fragment of the invention, under conditions suitable for binding of the antibody or fragment to HMGB polypeptide present in the sample. If antibody-HMGB complexes or antigen-binding fragment-HMGB complexes are detected, their presence is indicative of HMGB polypeptide in the sample. In another embodiment, the invention is a test kit for use in detecting the presence of a vertebrate HMGB polypeptide or a portion thereof in a sample. The test kit comprises an antibody or antigen-binding fragment of the invention and one or more ancillary reagents suitable for detecting the presence of a complex between the antibody or antigen-binding fragment and the HMGB polypeptide.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is the amino acid sequence of a human (Homo sapiens) HMGBl polypeptide (SEQ ID NO:l). The underlined amino acid residues delineate the A box, B box and acidic tail domains of the HMGBl polypeptide. FIG. 2A is the amino acid sequence of a polypeptide comprising an A box of human (Homo sapiens) HMGBl (SEQ ID NO:2). The underlined amino acid residues delineate the A box of the HMGBl polypeptide, which is the same for human, rat and mouse. FIG. 2B is the amino acid sequence of a B box of a human (Homo sapiens) HMGBl polypeptide (SEQ ID NO:3). The underlined amino acid residues delineate the B box of the HMGBl polypeptide, which is the same for human, rat and mouse. FIG. 3 A is the nucleotide sequence encoding the recombinant CBP-Rat HMGBl peptide (SEQ ID NO:4) that was used as an immunogen to generate monoclonal antibodies. FIG. 3B is the encoded amino acid sequence of the recombinant CBP-Rat HMGBl peptide (SEQ ID NO:5) that was used as an immunogen to generate monoclonal antibodies. The CBP affinity tag, which was removed by thrombin cleavage, is indicated in lower case letters and the normal translation initiation amino acid (i.e., M) of HMGBl is underlined. FIG.4A is the nucleotide sequence encoding the V_H domain of 6E6 HMGBl mAb (SEQ ID NO:6). FIG. 4B is the encoded amino acid sequence of the V_H domain of 6E6 HMGBl mAb (SEQ ID NO:7); CDRs are underlined. FIG. 4C is the nucleotide sequence encoding the V_κ domain of 6E6 HMGBl mAb (SEQ ID NO:8). FIG. 4D is the encoded amino acid sequence of the V_κ domain of 6E6

HMGBl mAb (SEQ ID NO:9); CDRs are underlined. FIG. 5 A is the nucleotide sequence encoding the V_H domain of 2E11 HMGBl mAb (SEQ ID NO:10). FIG. 5B is the encoded amino acid sequence of the V_H domain of 2E11 HMGB 1 mAb (SEQ ID NO: 11); CDRs are underlined. FIG. 5C is the nucleotide sequence encoding the V_κ domain of 2E11 HMGBl mAb (SEQ ID NO: 12). FIG. 5D is the encoded amino acid sequence of the V_κ domain of 2E11 HMGBl mAb (SEQ ID NO: 13); CDRs are underlined. FIG. 6A is the nucleotide sequence encoding the V_H domain of 10D4

HMGBl mAb (SEQ ID NO: 14). FIG. 6B is the encoded amino acid sequence of the V_H domain of 10D4 HMGBl mAb (SEQ ID NO: 15); CDRs are underlined. FIG. 6C is the nucleotide sequence encoding the V_κ domain of 10D4 HMGB 1 mAb (SEQ ID NO: 16). FIG. 6D is the encoded amino acid sequence of the V_κ domain of 10D4 HMGBl mAb (SEQ ID NO: 17); CDRs are underlined. FIG. 7 is a table summarizing characteristics of various anti-HMGBl monoclonal antibodies. Clone names, the immunogen used to generate the monoclonal antibody (either rat HMGBl-CBP (SEQ ID NO:5 (see FIG. 3B) or the B box of a human HMGBl polypeptide (SEQ ID NO:3 (see FIG. 2B)), the isotype, binding domains for the antibodies and results of in vivo CLP assays are indicated. FIG. 8 is a histogram depicting inhibition of TNF release by particular anti- HMGB1 monoclonal antibodies. Mouse TNF was induced by stimulating RAW 5 264.7 cells with 0.1 μg/ml of recombinant CBP-Rat HMGBl peptide (SEQ ID NO:5). Where indicated, 20 μg/ml of 6E6 HMGBl mAb (6E6), 10D4 HMGBl mAb (10D4), 2E11 HMGBl mAb (2E11), 9G2 HMGBl mAb (9G2) or mouse IgG control antibody (mlgG) were added. All samples were done in duplicate and error bars are indicated.

10 FIG. 9 is a histogram depicting inhibition of TNF release by various anti- HMGB1 monoclonal antibodies. Mouse TNF was induced by stimulating RAW 264.7 cells with 0.01 μg/ml or 0.1 μg/ml of recombinant CBP-Rat HMGBl peptide (SEQ ID NO:5). Where indicated, 20 μg ml of 3G8 HMGBl mAb (3G8), 1A9 HMGBl mAb (1 A9), 9G2 HMGBl mAb (9G2), 6E6 HMGBl mAb (6E6), 2E11

15 HMGBl mAb (2E11), 10D4 HMGBl mAb (10D4), 6H9 HMGBl mAb (6H9) or mouse IgG control antibody (IgG) were added. i FIG. 10 is a graph of the effect of various anti-HMGBl monoclonal antibodies (6E6 HMGBl mAb (mAB (6E6)); 2E11 HMGBl mAb (mAB (2E11)); 9G2 HMGBl mAb (mAB (9G2))) and a control IgG antibody (Ctrl IgG) on survival

20 of mice over time (days) after cecal ligation and puncture (CLP). FIG. 11 depicts a series of individual Western blots of samples containing either CHO HMGBl or CHO HMGB2 and possibly recombinant HMGB1-His₆ (labeled as CHO HMGB2, rec-HMGBl-His₆), which were probed with either an anti-His Tag antibody (Anti-His Tag), an anti-HMGB2 antibody (Anti-HMGB2), an

25 anti-HMGB 1/2 monoclonal antibody (Anti-HMGB 1/2 mAb) or particular anti- HMGB1 monoclonal antibodies (i.e., 2E11 HMGBl mAb (CT3-2E11), 1G3 HMGBl mAb (CT3-1G3), 6H9 HMGBl mAb (CT3-6H9), 2G7 HMGBl mAb (CT3-2G7), 2G5 HMGBl mAb (CT3-2G5) and 6E6 HMGBl mAb (CT3-6E6)). FIG. 12 is an amino acid sequence alignment of HMGBl polypeptide

30 sequences from rat (SEQ ID NO:18; labeled "rat # P07155" or "rat" (GenBank Accession No. P07155)), mouse (Mus musculus) (SEQ ID NO: 18; labeled "mouse #AAA20508" or "mouse" (GenBank Accession No. AAA20508)) and human (Homo sapiens) (SEQ ID NO: 1; labeled "human #AAA64970" or "human" (GenBank Accession No. AAA64970)). The A box and B box domains are underlined and labeled as indicated. FIG. 13A is a table depicting individual peptides corresponding to particular regions of human HMGBl, their respective amino acid sequences, molecular weights, calculated masses required to produce a 1 mM stock solution and available amounts. FIG. 13B is a histogram depicting the results of HMGBl peptide binding experiments. Biotinylated peptides corresponding to particular 18 amino acid regions of human HMGBl and a longer peptide corresponding to amino acid residues 9-85 of human HMGBl (listed in FIG. 13A) were prepared and analyzed for binding to particular anti-HMGB 1 monoclonal antibodies (i.e., 2E11 HMGBl mAb (2E11), 6E6 HMGBl mAb (6E6), 6H9 HMGBl mAb (6H9) and 2G7 HMGBl mAb (2G7)) by ELISA. FIG. 14 is a graph depicting the results of anti-HMGB 1 monoclonal antibody IELISAS. In the ELISAs, particular anti-HMGBl monoclonal antibodies (2E11 HMGBl mAb (2E11), 2G5 HMGBl mAb (2G5), 2G7 HMGBl mAb (2G7) and 6E6 HMGBl mAb (6E6)) were used as capture antibodies and a polyclonal HMGBl antibody was used as the detector antibody. FIG. 15 is a graph depicting the results of anti-HMGBl monoclonal antibody ELISAs. hi the ELISAs, particular anti-HMGBl monoclonal antibodies (2E11 HMGBl mAb (2E11), 2G5 HMGBl mAb (2G5), 2G7 HMGBl mAb (2G7) and 6E6 HMGBl mAb (6E6)) were used as capture antibodies and 6E6 HMGBl mAb was used as the detector antibody. FIG. 16 is a graph depicting a dose response curve for anti-HMGBl monoclonal antibody 6E6 HMGBl mAb (6E6; at doses of 1 μg/mouse, 10 μg/mouse or 100 μg/mouse as labeled) or a control IgG antibody (Control IgG) on survival of mice over time (days) after cecal ligation and puncture (CLP). FIG. 17 is a sequence alignment of HMGBl polypeptide sequences of an

HMGBl polypeptide expressed in CHO cells (CHOHMGB1; SEQ ID NO:36); rat (ratHMGBl; SEQ LD NO: 18), mouse (musHMGBl; SEQ ID NO:18), human (huHMGBl; SEQ ID NO:74), pig (susHMGBl; SEQ ID NO:37) and cow (bosHMGBl; SEQ LO NO:38) FIG. 18 A is a nucleotide sequence of a human recombinant HMGB 1 polypeptide containing a 5' 6 HIS tag (rec-HMGB 1 -His₆; SEQ ID NO:39). Cloning sequences are indicated in lower case. FIG. 18B is the encoded amino acid sequence of the human recombinant HMGBl polypeptide containing a 5' 6 HIS tag (rec-HMGB 1-His₆; SEQ ID NO:40). FIG. 19A is the nucleotide sequence encoding the V_H domain of 2G7 HMGBl mAb (SEQ ID NO:41). FIG.19B is the encoded amino acid sequence of the V_H domain of 2G7 HMGBl mAb (SEQ ID NO:42); CDRs are underlined. FIG. 19C is the nucleotide sequence encoding the V_κ domain of 2G7 HMGBl mAb (SEQ ID NO:43). FIG. 19D is the encoded amino acid sequence of the V_κ domain of 2G7

HMGBl mAb (SEQ ID NO:44); CDRs are underlined. FIG. 20 is a histogram depicting the results of HMGBl peptide binding experiments. Biotinylated peptides corresponding to either amino acid residues 46- 63 or 61-78 of HMGBl were prepared and analyzed for binding to 2G7 HMGBl mAb (2G7) by ELISA. FIG. 21 is a histogram depicting the results of HMGBl peptide binding experiments. Biotinylated peptides corresponding to either amino acid residues 46- 63 or 151-168 of HMGBl were prepared and analyzed for binding to 2E11 HMGBl mAb (2El l) by ELISA. FIG. 22 is a histogram depicting the results of HMGB 1 and HMGB2 peptide binding experiments. Peptides corresponding to either amino acid residues 46-63 of human HMGBl (labeled "huHMGBl-46-63-B"), amino acid residues 46-63 of human HMGB2 (labeled "huHMGB2-46-63-B"), amino acid residues 53-70 of human HMGBl (labeled "huHMGB 1-53-70"), or amino acid residues 61-78 of human HMGBl (labeled "huHMGBl-61-78-B") were prepared and analyzed for binding to 2G7 HMGBl mAb (2G7) or avidin by ELISA. FIG. 23 is a table depicting the results of HMGBl and HMGB2 peptide binding experiments. Listed in the table are various peptides, their respective amino acid sequences and whether the peptides bind 2G7 HMGBl mAb. The listed peptides include: a peptide corresponding to amino acid residues 40-57 of human HMGBl (labeled "Human HMGB 1-40-57"), a peptide corresponding to amino acid residues 46-63 of human HMGBl (labeled "Human HMGB1-46-63-B), a peptide corresponding to amino acid residues 53-70 of human HMGBl (labeled "Human HMGB 1-53-70"), a peptide corresponding to amino acid residues 46-63 of human HMGB2 (labeled "Human HMGB2-46-63-B"), and a peptide consisting of a scrambled amino acid sequence, wherein the amino acid residues that were 1 scrambled were those of amino acid residues 46-63 of human HMGBl (labeled "Human HMGBl-46-63-scr"). FIG. 24 is a table depicting the results of HMGBl peptide binding experiments. Listed in the table are various peptides, their respective amino acid sequences and whether the peptides bind 6E6 HMGBl mAb. The listed peptides include: a peptide corresponding to amino acid residues 53-70 of human HMGBl (labeled "Human HMGB 1-53-70"), a peptide corresponding to amino acid residues 61-78 of human HMGBl (labeled "Human HMGB 1-61 -78 -B"), a peptide corresponding to amino acid residues 67-84 of human HMGBl (labeled "Human HMGB 1-67-84"), and a peptide consisting of a scrambled amino acid sequence, wherein the amino acid residues that were scrambled were those of amino acid residues 61-78 of human HMGBl (labeled "Human HMGBl-61-78_scr"). FIG. 25 is a table depicting the results of HMGBl peptide binding experiments. Listed in the table are various peptides, their respective amino acid sequences and whether the peptides bind 2E11 HMGBl mAb. The listed peptides include: a peptide corresponding to amino acid residues 143-160 of human HMGBl (labeled "Human HMGB1-143-160"), a peptide corresponding to amino acid residues 151-168 of human HMGBl (labeled "Human HMGB1-151-168-B"), a peptide corresponding to amino acid residues 157-174 of human HMGBl (labeled "Human HMGBl-157-174"), and a peptide consisting of a scrambled amino acid sequence, wherein the amino acid residues that were scrambled were those of amino acid residues 151-168 of human HMGBl (labeled "Human HMGB 1-15 l-168_scr"). FIG. 26 is a histogram summarizing the results of peptide binding experiments and depicting the mapped epitopes of HMGBl that are recognized by 2G7 HMGB 1 mAb (2G7), 6E6 HMGB 1 mAb (6E6), 2G5 HMGB 1 mAb (2G5), 6H9 HMGBl mAb (6H9) and 2E11 HMGBl mAb (2E11). FIG. 27A is a mass spectrum of intact, non-reduced 6E6 HMGBl mAb. FIG. 27B is a mass spectrum of 6E6 HMGBl mAb, which was reduced by treatment with DTT. FIG. 27C is a mass spectrum of the light chains of 6E6 HMGBl mAb, which were reduced by treatment with DTT. FIG. 27D is a mass spectrum of the heavy chains of 6E6 HMGBl mAb, which were reduced by treatment with DTT. FIG. 28 is a graph of the effect of administration of various doses (either 0.004 mg/kg, 0.04 mg kg or 0.4 mg/kg) of 2G7 HMGB 1 mAb or a control IgG antibody (0.4 mg/kg) on survival of mice over time (days) after cecal ligation and puncture (CLP). FIG. 29 is a table summarizing CLP survival percentages in mice administered various doses (either 4 mg/kg, 0.4 mg/kg, 0.04 mg/kg or 0.004 mg/kg) of 6E6 HMGB 1 mAb (6E6), 2G7 HMGB 1 mAb (2G7), or control IgG. FIG. 30 is the amino acid sequence of a human (Homo sapiens) HMGB2 polypeptide (SEQ ID NO:54; GenBank Accession No. M83665). FIG 31 A is the amino acid sequence of a human (Homo sapiens) HMGBl polypeptide (SEQ ID NO:74). FIG 3 IB is an A box of a human (Homo sapiens) HMGB 1 polypeptide (SEQ

LO NO:75). FIG 31 C is a B box of a human (Homo sapiens) HMGBl polypeptide (SEQ ID NO:76). FIG. 32 is a histogram depicting inhibition of TNF release by various anti- HMGBl monoclonal antibodies. Mouse TNF was induced by stimulating RAW 264.7 cells with 0.1 μg/ml of recombinant CBP-Rat HMGBl peptide (SEQ ID NO:5). Where indicated, various HMGBl monoclonal antibodies (cultured supernatants) were added to give a final concentration of 13%. The following antibodies were tested: 1 A9 HMGBl mAb (1A9); 2E11 HMGBl mAb (2E11); 2G5 HMGBl mAb (2G5); 2G7 HMGBl mAb (2G7); 3G8 HMGBl mAb (3G8); 4H11 HMGBl mAb (4H11); 3-5A6 HMGBl mAb (5A6); 6E6 HMGBl mAb (6E6); 9G2 HMGBl mAb (9G2); 4C9 HMGBl mAb (4C9); and 6H9 HMGBl mAb (6H9). The initial dark bar depicts TNF release in the absence of any antibodies. FIG. 33 is a histogram depicting inhibition of TNF release by various anti- HMGBl monoclonal antibodies. Mouse TNF was induced by stimulating RAW 264.7 cells with 0.1 μg/ml of recombinant CBP-Rat HMGBl peptide (SEQ ID NO: 5). Where indicated, various HMGBl monoclonal antibodies (cultured supernatants) were added to give a final concentration of 13%. The following antibodies were tested: 7H3 HMGBl mAb (7H3); 9H3 HMGBl mAb (9H3); 10D4 HMGBl mAb (10D4); 1C3 HMGBl mAb (1C3); 3E10 HMGBl mAb (3E10); 4A10 HMGBl mAb (4A10); 5C12 HMGBl mAb (5C12); and 7G8 HMGBl mAb (7G8). The initial dark bar depicts TNF release in the absence of any antibodies.

DETAILED DESCRIPTION OF THE INVENTION In various embodiments, the present invention is drawn to antibodies or antigen-binding fragments thereof that bind to a vertebrate high mobility group box (HMGB) polypeptide, methods of detecting and/or identifying an agent that binds to an HMGB polypeptide, methods of treating a condition in a subject characterized by activation of an inflammatory cytokine cascade and methods of detecting an HMGB polypeptide in a sample.

Antibodies and Antibody Producing Cells In one embodiment, the present invention encompasses antibodies or antigen-binding fragments thereof that bind to HMGB polypeptides. The antibodies of the invention can be polyclonal or monoclonal, and the term "antibody" is intended to encompass both polyclonal and monoclonal antibodies. The terms polyclonal and monoclonal refer to the degree of homogeneity of an antibody preparation, and are not intended to be limited to particular methods of production. In one embodiment, the antibody or antigen-binding fragment is a monoclonal antibody or antigen-binding fragment thereof. The term "monoclonal antibody" or "monoclonal antibody composition", as used herein, refers to a population of antibody molecules that contain only one species of an antigen binding site capable of immunoreacting with a particular epitope of a polypeptide of the invention. A monoclonal antibody composition thus typically displays a single binding affinity for a particular polypeptide of the invention with which it immunoreacts. The term "antibody" as used herein also encompasses functional fragments of antibodies, including fragments of chimeric, humanized, primatized, veneered or single chain antibodies. Functional fragments include antigen-binding fragments of antibodies that bind to an HMGB polypeptide (e.g., a mammalian HMGB polypeptide (e.g. a mammalian HMGBl polypeptide)). For example, antibody fragments capable of binding to an HMGB polypeptide or a portion thereof, include, but are not limited to Fv, Fab, Fab' and F(ab')₂ fragments. Such fragments can be produced by enzymatic cleavage or by recombinant techniques. For example, papain or pepsin cleavage can generate Fab or F(ab')₂ fragments, respectively. Other proteases with the requisite substrate specificity can also be used to generate Fab or F(ab')₂ fragments. Antibodies can also be produced in a variety of truncated forms using antibody genes in which one or more stop codons have been introduced upstream of the natural stop site. For example, a chimeric gene encoding a F(ab')₂ heavy chain portion can be designed to include DNA sequences encoding the CH_] domain and hinge region of the heavy chain. Single chain antibodies, and chimeric, humanized or primatized (CDR- grafted), or veneered antibodies, as well as chimeric, CDR-grafted or veneered single chain antibodies, comprising portions derived from different species, and the like are also encompassed by the present invention and the term "antibody". The various portions of these antibodies can be joined together chemically by conventional techniques, or can be prepared as a contiguous protein using genetic engineering techniques. For example, nucleic acids encoding a chimeric or humanized chain can be expressed to produce a contiguous protein. See, e.g., Cabilly et al, U.S. Patent No. 4,816,567; Cabilly et al, European Patent No. 0,125,023 Bl; Boss et al, U.S. Patent No. 4,816,397; Boss et al, European Patent No. 0,120,694 Bl; Neuberger, M.S. et al, WO 86/01533; Neuberger, M.S. et al, European Patent No. 0,194,276 Bl; Winter, U.S. Patent No. 5,225,539; Winter, European Patent No. 0,239,400 Bl; Queen et al, European Patent No. 0 451 216 Bl; and Padlan, E.A. et al, EP 0 519 596 Al. See also, Newman, R. et al, BioTechnology, 10: 1455-1460 (1992), regarding primatized antibody, and Ladner et al, U.S. Patent No. 4,946,778 and Bird, R.E. et al, Science, 242: 423-426 (1988)) regarding single chain antibodies. Humanized antibodies can be produced using synthetic or recombinant DNA technology using standard methods or other suitable techniques. Nucleic acid (e.g., cDNA) sequences coding for humanized variable regions can also be constructed using PCR mutagenesis methods to alter DNA sequences encoding a human or humanized chain, such as a DNA template from a previously humanized variable region (see e.g., Kamman, M., et ah, Nucl. Acids Res., 17: 5404 (1989)); Sato, K., et al, Cancer Research, 53: 851-856 (1993); Daugherty, B.L. et al, Nucleic Acids Res., 19(9): 2471-2476 (1991); and Lewis, A.P. and J.S. Crowe, Gene, 101: 297-302 (1991)). Using these or other suitable methods, variants can also be readily produced. In one embodiment, cloned variable regions can be mutated, and sequences encoding variants with the desired specificity can be selected (e.g., from a phage library; see e.g., Krebber et al, U.S. 5,514,548; Hoogenboom βt al, WO 93/06213). The antibody can be a humanized antibody comprising one or more immunoglobulin chains (e.g., an antibody comprising a CDR of nonhuman origin (e.g., one or more CDRs derived from an antibody of nonhuman origin) and a framework region derived from a light and/or heavy chain of human origin (e.g., CDR-grafted antibodies with or without framework changes)), hi one embodiment, the antibody or antigen-binding fragment thereof comprises the light chain CDRs (CDR1, CDR2 and CDR3) and heavy chain CDRs (CDR1, CDR2 and CDR3) of a particular immunoglobulin. In another embodiment, the antibody or antigen-binding fragment further comprises a human framework region. The antibodies described herein can also be conjugated to an agent. In one embodiment, the agent is a label, for example, a radioisotope, an epitope label (tag), an affinity label (e.g., biotin, avidin), a spin label, an enzyme, a fluorescent group or a chemilummescent group. Labeled antibodies or antigen-binding fragments of the present invention can be used, e.g., in the diagnostic and/or prognostic methods described herein. In another embodiment, the antibody is conjugated to a drug, toxin or anti-inflammatory agent. Conjugation of a drug, toxin or anti-inflammatory agent to the anti-HMGB antibodies and antigen-binding fragments of the invention allows for targeting of these agents to sites of HMGB expression and/or activity. Drugs and toxins that can be conjugated to the antibodies of the present invention include, for example, chemotherapeutic agents (e.g., mitomycin C, paxlitaxol, methotrexate, 5- fluorouracil, cisplatin, cyclohexamide), toxins (e.g., ricin, gelonin) and other agents described herein (e.g., the agents described for combination therapy). Anti- inflammatory agents that can be conjugated include, e.g., those described herein. Antibodies that are specific for an HMGB polypeptide (e.g., a mammalian

HMGB polypeptide) can be raised against an appropriate immunogen, such as an isolated and or recombinant HMGB polypeptide or a portion thereof (including synthetic molecules, such as synthetic peptides). Antibodies can also be raised by immunizing a suitable host (e.g., mouse) with cells that express an HMGB polypeptide, such as GH3 pituicytes, macrophage cells (e.g., RAW 246.7 cells, human macrophage cells), peripheral blood mononuclear cells (PBMCs (e.g., human PBMCs)), primary T cells (e.g., human primary T cells), adrenal cells (e.g., rat adrenal PC-12 cells, human adrenal cells), and kidney cells (e.g., rat primary kidney cells, human primary kidney cells). In addition, cells expressing a recombinant HMGB polypeptide (e.g., a mammalian HMGB polypeptide), such as transfected cells, can be used as an immunogen or in a screen for an antibody that binds thereto (See e.g., Chuntharapai et al, J. Immunol, 152: 1783-1789 (1994); Chuntharapai et al, U.S. Patent No. 5,440,021). Preparation of immunizing antigen, and polyclonal and monoclonal antibody production can be performed using any suitable technique. A variety of methods have been described (see e.g., Kohler et al, Nature, 256: 495-497 (1975) and Eur. J. Immunol 6: 511-519 (1976); Milstein et al, Nature 266: 550-552 (1977); Koprowski et al, U.S. Patent No. 4,172,124; Harlow, E. and D. Lane, 1988, Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory: Cold Spring Harbor, NY); Current Protocols In Molecular Biology, Vol. 2 (Supplement 27, Summer '94), Ausubel, F.M. et al, Eds., (John Wiley & Sons: New York, NY), Chapter 11, (1991)). Generally, as exemplified herein, a hybridoma is produced by fusing a suitable immortal cell line (e.g., a myeloma cell line such as SP2/0, P3X63Ag8.653 or a heteromyeloma) with antibody-producing cells. Antibody- producing cells can be obtained from the peripheral blood or, preferably the spleen or lymph nodes, of humans or other suitable animals immunized with the antigen of interest. The fused cells (hybridomas) can be isolated using selective culture conditions, and cloned by limiting dilution. Cells that produce antibodies with the desired specificity can be selected by a suitable assay (e.g., ELISA). Other suitable methods of producing or isolating antibodies of the requisite specificity (e.g., human antibodies or antigen-binding fragments) can be used, including, for example, methods that select recombinant antibody from a library (e.g., a phage display library). Transgenic animals capable of producing a repertoire of human antibodies (e.g., Xenomouse^® (Abgenix, Fremont, CA)) can be produced using suitable methods (see e.g., Jakobovits et al, Proc. Natl. Acad. Sci. USA, 90: 2551-2555 (1993); Jakobovits et al, Nature, 362: 255-258 (1993)). Additional methods that are suitable for production of transgenic animals capable of producing a repertoire of human antibodies have been described (e.g., Lonberg et al, U.S. Patent No. 5,545,806; Surani et al, U.S. Patent No. 5,545,807; Lonberg et al, WO97/13852). In one embodiment, the antibody or antigen-binding fragment thereof has specificity for an HMGB polypeptide (e.g., a mammalian HMGB polypeptide). In a particular embodiment, the antibody or antigen-binding fragment thereof has specificity for an HMGBl polypeptide (e.g., a human HMGBl polypeptide such as depicted in SEQ ID NO:l and/or SEQ ID NO:74). In another embodiment, the antibody or antigen-binding fragment thereof is an IgG or an antigen-binding fragment of an IgG. In another embodiment, the antibody or antigen-binding fragment thereof is an IgGl or an antigen-binding fragment of an IgGl. In still other embodiments, the antibody or antigen-binding fragment thereof is an IgG2a, IgG2b, IgG3 antibody, or an antigen-binding fragment of any of the foregoing. In another embodiment, the antibody or antigen-binding fragment can bind to an HMGB polypeptide and inhibit (reduce or prevent) one or more functions of the ^• HMGB polypeptide. Such HMGB functions include, e.g., increasing inflammation (see, e.g., PCT Publication No. WO 02/092004), increasing release of a proinflammatory cytokine from a cell (see, e.g., PCT Publication No. WO 02/092004), binding to RAGE, binding to TLR2, chemoattraction (see, e.g., Degryse et al, J. Cell Biol. 152(6): 1197-1206 (2001); the entire teachings of which are incorporated herein by reference), and activation of antigen presenting cells (see, e.g., WO 03/026691; the entire teachings of which are incorporated herein by reference). In one embodiment, the antibody is a human antibody or an antigen-binding fragment thereof. In another embodiment, the antibody is a humanized antibody or an antigen-binding fragment thereof. In yet another embodiment, the antibody or antigen-binding fragment can inhibit binding of a polypeptide (e.g., RAGE, TLR2) to an HMGB polypeptide and or inhibit one or more functions mediated by binding of the HMGB polypeptide and the other polypeptide. hi certain embodiments, the antibodies or antigen-binding fragments thereof specifically bind to HMGB epitopes or antigenic determinants (e.g., HMGB epitopes, HMGB A box epitopes, HMGB B box epitopes). As described herein, an antibody or antigen-binding fragment thereof can be screened without undue experimentation for the ability to inhibit release of a proinflammatory cytokine using standard methods. Anti-HMGB A-box antibodies and anti-HMGB B box antibodies that can inhibit the production of a proinflammatory cytokine and/or the release of a proinflammatory cytokine from a cell, and/or inhibit a condition characterized by activation of an inflammatory cytokine cascade, are within the scope of the present invention. In one embodiment, the antibody or antigen-binding fragment of the invention can inhibit the production of TNF, JL-1 β, and/or LL-6. In another embodiment, the antibody or antigen-binding fragment of the invention can inhibit the production of TNF (e.g., TNF- ). As described herein, monoclonal antibodies designated "6E6 HMGBl mAb", "2E11 HMGBl mAb", "6H9 HMGBl mAb", "10D4 HMGBl mAb" and "2G7 HMGBl mAb", all of which bind to HMGBl have been produced. In addition, other monoclonal antibodies designated "9G2 HMGBl mAb", "1 A9 HMGBl mAb", "3G8 HMGBl mAb", "2G5 HMGBl mAb", "4H11 HMGBl mAb", "7H3 HMGBl mAb", "3-5 A6 HMGBl mAb", "9G1 HMGBl mAb", "4C9 HMGBl mAb", "9H3 HMGBl mAb", "1C3 HMGBl mAb", "5C12 HMGBl mAb", "3E10 HMGB 1 mAb", "7G8 HMGB 1 mAb" and "4A10 HMGB 1 mAb" have been produced. All but 9G2 HMGBl mAb and 1A9 HMGBl mAb have been shown to bind HMGBl. 9G2 HMGBl mAb and 1A9 HMGBl mAb appear to bind to the CBP region of the immunogen (which is not cleaved in a small percentage of the immunogen). 6E6 HMGBl mAb, also referred to as 6E6-7-1-1 or 6E6, can be produced by murine hybridoma 6E6 HMGBl mAb, which was deposited on September 3, 2003, on behalf of Critical Therapeutics, Inc., 675 Massachusetts Avenue, 14^th Floor, Cambridge, MA 02139, U.S.A., at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia 20110, U.S.A., under Accession No. PTA-5433. The invention relates to murine hybridoma 6E6 HMGBl mAb, to the antibody it produces and to nucleic acids encoding the antibody. 2E11 HMGBl mAb, also referred to as 2E11-1-1-2 or 2E11, can be produced by murine hybridoma 2E11 HMGBl mAb, which was deposited on September 3, 2003, on behalf of Critical Therapeutics, Inc., 675 Massachusetts Avenue, 14^th Floor, Cambridge, MA 02139, U.S.A., at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia 20110, U.S.A., under Accession No. PTA-5431. The invention relates to murine hybridoma 2E11 HMGBl mAb, to the antibody it produces and to nucleic acids encoding the antibody. 6H9 HMGBl mAb, also referred to as 6H9-1-1-2 or 6H9, can be produced by murine hybridoma 6H9 HMGBl mAb, which was deposited on September 3, 2003, on behalf of Critical Therapeutics, Inc., 675 Massachusetts Avenue, 14^th Floor, Cambridge, MA 02139, U.S.A., at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia 20110, U.S.A., under Accession No. PTA-5434. The invention relates to murine hybridoma 6H9 HMGBl mAb, to the antibody it produces and to nucleic acids encoding the antibody. 10D4 HMGBl mAb, also referred to as 10D4-1-1-1-2 or 10D4, can be produced by murine hybridoma 10D4 HMGBl mAb, which was deposited on September 3, 2003, on behalf of Critical Therapeutics, Inc., 675 Massachusetts Avenue, 14^th Floor, Cambridge, MA 02139, U.S.A., at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia 20110, U.S.A., under Accession No. PTA-5435. The invention relates to murine hybridoma 10D4 HMGBl mAb, to the antibody it produces and to nucleic acids encoding the antibody. 2G7 HMGBl mAb, also referred to as 3-2G7-1-1-1 or 2G7, can be produced by murine hybridoma 2G7 HMGB 1 mAb, which was deposited on September 3,

2003, on behalf of Critical Therapeutics, Inc., 675 Massachusetts Avenue, 14^th Floor, Cambridge, MA 02139, U.S.A., at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia 20110, U.S.A., under Accession No. PTA-5432. The invention relates to murine hybridoma 2G7 HMGBl mAb, to the antibody it produces and to nucleic acids encoding the antibody. For cultivation of the above identified murine hybridomas (e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2G7 HMGBl mAb), DMEM, 10% FCS, 1% IL-6, 1% L-glutamine and 1% Pen-Strep should be added. 9G2 HMGB 1 mAb, also referred to as 9G2-7- 1 - 1 - 1 or 9G2, can be produced by murine hybridoma 9G2 HMGBl mAb. The invention relates to murine hybridoma 9G2 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 1A9 HMGBl mAb, also referred to as 1A9-1-2-1-4 or 1A9, can be produced by murine hybridoma 1 A9 HMGBl mAb. The invention relates to murine hybridoma 1A9 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 3G8 HMGBl mAb, also referred to as 3G8-7-2-1-5 or 3G8, can be produced by murine hybridoma 3G8 HMGBl mAb. The invention relates to murine hybridoma 3G8 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 2G5 HMGBl mAb, also referred to as 3-2G5-4-1-2 or 2G5, can be produced by murine hybridoma 2G5 HMGBl mAb. The invention relates to murine hybridoma 2G5 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 4H11 HMGBl mAb, also referred to as 4H11, can be produced by murine hybridoma 4H11 HMGB mAb. The invention relates to murine hybridoma 4H11 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 7H3 HMGBl mAb, also referred to as 7H3, can be produced by murine hybridoma 7H3 HMGBl mAb. The invention relates to murine hybridoma 7H3 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 3-5 A6 HMGBl mAb, also referred to as 3-5 A6 or 5A6, can be produced by murine hybridoma 3-5A6 HMGBl mAb. The invention relates to murine hybridoma 3-5 A6 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 9G1 HMGBl mAb, also referred to as 9G1, can be produced by murine hybridoma 9G1 HMGBl mAb. The invention relates to murine hybridoma 9G1 HMGB 1 mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 4C9 HMGBl mAb, also referred to as 4C9, can be produced by murine hybridoma 4C9 HMGBl mAb. The invention relates to murine hybridoma 4C9 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 9H3 HMGBl mAb, also referred to as 9H3, can be produced by murine hybridoma 9H3 HMGBl mAb. The invention relates to murine hybridoma 9H3 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 1C3 HMGBl mAb, also referred to as 1C3-1-1-1-1 or 1C3, can be produced by murine hybridoma 1C3 HMGBl mAb. The invention relates to murine hybridoma 1C3 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 5C12 HMGBl mAb, also referred to as 5C12-1-1-1-1 or 5C12, can be produced by murine hybridoma 5C 12 HMGB 1 mAb. The invention relates to murine hybridoma 5C12 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 3E10 HMGBl mAb, also referred to as 3E10-5-4-1-1 or 3E10, can be produced by murine hybridoma 3E10 HMGBl mAb. The invention relates to murine hybridoma 3E 10 HMGB 1 mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 7G8 HMGBl mAb, also referred to as 7G8, can be produced by murine hybridoma 7G8 HMGBl mAb. The invention relates to murine hybridoma 7G8 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. 4A10 HMGBl mAb, also referred to as 4A10-1-3-1-1 or 4A10, can be produced by murine hybridoma 4A10 HMGBl mAb. The invention relates to murine hybridoma 4A10 HMGBl mAb, to the antibody it produces, and to nucleic acids encoding the antibody. In one embodiment, the antibody or antigen-binding fragment thereof is selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb and an antigen-binding fragment of any of the foregoing. In another embodiment, the antibody or antigen-binding fragment has the same or similar epitopic specificity of an antibody or antigen-binding fragment selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGB1 mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb and/or an antigen-binding fragment of any of the foregoing. Antibodies or antigen-binding fragments with an epitopic specificity that is the same as, or similar to, that of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb can be identified by a variety of suitable methods. For example, an antibody with the same or similar epitopic specificity as, e.g., 6E6 HMGBl mAb, can be identified based upon the ability to compete with 6E6 HMGB 1 mAb for binding to a HMGB polypeptide (e.g., a mammalian HMGB polypeptide (e.g., a mammalian HMGBl polypeptide)). In another example, the binding of, e.g., 6E6 HMGBl mAb, and the binding of an antibody with the same or similar epitopic specificity for a HMGB polypeptide can be inhibited by a single peptide (e.g., a natural peptide, a synthetic peptide). In various embodiments, the peptide can comprise, e.g., 9 to about 50 amino acids, 9 to about 40 amino acids, 9 to about 30 amino acids, 9 to about 25 amino acids or 9 to about 20 amino acids. As exemplified herein, 18 amino acid peptides corresponding to particular regions of the human HMGBl polypeptide were shown to bind to various HMGBl monoclonal antibodies. The studies described herein mapped epitopes within HMGBl that bind to particular HMGBl antibodies. For example, 2E11 HMGBl mAb was shown to bind a peptide corresponding to amino acids 151-168 of human HMGBl (amino acid residues 151- 168 of SEQ ID NO:l; i.e., LKEKYEKDIAAYRAKGKP (SEQ ID NO:30)). Additional studies suggest that 2E11 HMGBl mAb recognizes an epitope that is present in within amino acid residues 156-161, 155-161, 155-162, 156-162 and/or 156-163, of HMGBl (see Example 14). 6E6 HMGB 1 mAb and 6H9 HMGB 1 mAb were shown to bind to a peptide corresponding to amino acids 61-78 of human HMGBl (amino acid residues 61-78 of SEQ ID NO:l; i.e., EDMAKADKARYEREMKTY (SEQ ID NO:24)). Additional studies demonstrated that 6E6 HMGBl mAb recognizes an epitope that is present within amino acid residues 67-78 of HMGBl (see Example 13). 2G7 HMGB 1 mAb was shown to bind a peptide corresponding to amino acids 46-63 of human HMGBl (amino acid residues 46-63 of SEQ LD NO:l ; i.e., SERWKTMSAKEKGKFEDM (SEQ ID NO:23)) (see Example 10). Further studies demonstrated that 2G7 HMGBl mAb recognizes an epitope that is present within amino acid residues 53-63 of HMGBl (see Example 12). In addition, 2G7 HMGBl mAb does not bind to amino acid residues 46-63 of HMGB2 (SEQ ID NO:48), notwithstanding only a single amino acid difference between the HMGBl 46-63 peptide and the HMGB2 46-63 peptide (see Example 12). Thus, in one embodiment, the antibodies or antigen-binding fragments of the invention bind to HMGBl but not to HMGB2. In other embodiments, the antibodies or antigen- binding fragments of the invention bind to both HMGBl and HMGB2. These 18 amino acid peptides, or other peptides corresponding to particular regions of HMGBl, could be used in epitopic studies to determine if an antibody or antigen-binding fragment inhibited binding of the peptide to an antibody known to bind that peptide (e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb, others antibodies described herein). Thus, for example, an antibody or antigen-binding fragment to be tested for its epitopic specificity could be assayed with, e.g., 2E11 HMGBl mAb and a peptide corresponding to amino acids 151-168 of human HMGBl (which 2E11 HMGBl mAb is known to bind). In another example, an antibody with the same or similar epitopic specificity as an antibody of the invention (e.g., 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb) can be identified using a chimeric HMGB polypeptide (see e.g., Banks, G.C, et al, J. Biol. Chem. 274(23):16536-16544 (1999)). In one embodiment, the antibody or antigen-binding fragment can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGB 1 mAb, 10D4 HMGB 1 mAb, 2E11 HMGBl mAb and/or an antigen-binding fragment of any of the foregoing, for binding to an HMGB polypeptide (e.g., a mammalian HMGB polypeptide (e.g., a mammalian HMGBl polypeptide)). Such inhibition of binding can be the result of competition for the same or similar epitope or steric interference (e.g., where antibodies bind overlapping epitopes or adjacent epitopes). Inhibition by 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb, and/or an antigen-binding fragment of any of the foregoing, can also be due to a change in the conformation of the HMGB polypeptide that is induced upon antibody binding to the HMGB polypeptide. In another embodiment, the antibody or antigen-binding fragment thereof is selected from the group consisting of 3G8 HMGBl mAb, 2G5 HMGBl mAb, 4H11 HMGBl mAb, 7H3 HMGBl mAb, 3-5A6 HMGBl mAb, 9G1 HMGBl mAb, 4C9 HMGBl mAb, 9H3 HMGBl mAb, 1C3 HMGBl mAb, 5C12 HMGBl mAb, 3E10 HMGBl mAb, 7G8 HMGBl mAb, 4A10 HMGBl mAb, and an antigen-binding fragment of any of the foregoing. In one embodiment, the antibody or antigen-binding fragment has the epitopic specificity of an antibody or antigen-binding fragment selected from the group consisting of 3G8 HMGBl mAb, 2G5 HMGBl mAb, 4H11 HMGBl mAb, 7H3 HMGBl mAb, 3-5A6 HMGBl mAb, 9G1 HMGBl mAb, 4C9 HMGBl mAb, 9H3 HMGBl mAb, 1C3 HMGBl mAb, 5C12 HMGBl mAb, 3E10 HMGBl mAb, 7G8 HMGB 1 mAb, 4A10 HMGB 1 mAb, and an antigen-binding fragment of any of the foregoing. As described above, antibodies or antigen-binding fragments with an epitopic specificity that is the same as, or similar to, one or more of these antibodies or antigen-binding fragments can be identified by a variety of suitable methods (e.g., ' using methods described herein and/or known in the art). hi another embodiment, the antibody or antigen-binding fragment can compete with 3G8 HMGBl mAb, 2G5 HMGBl mAb, 4H11 HMGBl mAb, 7H3 HMGBl mAb, 3-5 A6 HMGBl mAb, 9G1 HMGBl mAb, 4C9 HMGBl mAb, 9H3 HMGBl mAb, 1C3 HMGBl mAb, 5C12 HMGBl mAb, 3E10 HMGBl mAb, 7G8 HMGBl mAb, 4A10 HMGBl mAb, and/or an antigen-binding fragment of any of the foregoing, for binding to an HMGB polypeptide (e.g., a mammalian HMGB polypeptide). As described above, inhibition of binding can be the result of competition for the same or similar epitope or steric interference (e.g., where antibodies bind overlapping epitopes or adjacent epitopes). Inhibition can also be due to a change in the conformation of the HMGB polypeptide that is induced upon binding of the antibody or antigen-binding fragment to the HMGB polypeptide. In one embodiment, the antibody or antigen-binding fragment thereof comprises the six CDRs (light chain CDRs (CDR1, CDR2 and CDR3) and heavy chain CDRs (CDR1, CDR2 and CDR3)) of an antibody selected from the group consisting of 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGB 1 mAb, 10D4 HMGBl mAb and 2E11 HMGBl mAb. In another embodiment, the antibody is a humanized antibody that comprises the light chain CDRs (CDR1, CDR2 and CDR3) and heavy chain CDRs (CDR1, CDR2 and CDR3) of an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and 2E11 HMGBl mAb. In other embodiments, the antibody or antigen-binding fragment thereof comprises the six CDRs (light chain CDRs (CDR1, CDR2 and CDR3) and heavy chain CDRs (CDR1, CDR2 and CDR3)) of any other antibody described herein. another embodiment, the antibody or antigen-binding fragment thereof comprises from one to six of the light chain and heavy chain CDRs of an antibody of the invention (e.g., 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGB 1 mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb). For example, the antibody or antigen- binding fragment can comprise one, two, three, four, five or six, of the light chain and heavy chain CDRs. In another embodiment, the antibody or antigen-binding fragment thereof comprises at least one light chain CDR or heavy chain CDR from one antibody of the invention and at least one light chain CDR or heavy chain CDR from a different antibody of the invention (e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb). For example, an antibody or antigen-binding fragment could comprise one or more CDRs from 6E6 HMGBl mAb and one or more CDRs from 6H9 HMGBl mAb. Antibodies and antigen-binding fragments combining other combinations of CDRs from different antibodies of the invention are also encompassed. In another embodiment, the antibody or antigen-binding fragment thereof comprises the six CDRs (light chain CDRs (CDR1, CDR2 and CDR3) and heavy chain CDRs (CDR1, CDR2 and CDR3)) of an antibody selected from the group consisting of 3G8 HMGB 1 mAb, 2G5 HMGB 1 mAb, 4H11 HMGB 1 mAb, 7H3 HMGBl mAb, 3-5A6 HMGBl mAb, 9G1 HMGBl mAb, 4C9 HMGBl mAb, 9H3 HMGB1 mAb, 1C3 HMGBl mAb, 5C12 HMGBl mAb, 3E10 HMGBl mAb, 7G8 HMGBl mAb and 4A10 HMGBl mAb. In another embodiment, the antibody or antigen-binding fragment thereof comprises from one to six of the light chain, and heavy chain CDRs of one of these antibodies. In certain embodiments, the antibody or antigen-binding fragment comprises one or more CDRs that are at least 80% identical, at least 90% identical, or at least 95%o identical, to a CDR of an antibody of the invention (e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb). In other embodiments, the antibody or antigen-binding fragment comprises one or more CDRs that are at least 80% similar, at least 90% similar, or at least 95% similar, to a CDR of an antibody of the invention. Methods for determining sequence identity and similarity of two polypeptides are described herein and/or are well known in the art. The invention also relates to a bispecific antibody, or functional fragment thereof (e.g., F(ab')₂), which binds to an HMGB polypeptide and at least one other antigen (e.g., tumor antigen, viral antigen). In a particular embodiment, the bispecific antibody, or functional fragment thereof, has the same or similar epitopic specificity as 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb, and at least one other antibody. Bispecific antibodies can be secreted by triomas and hybrid hybridomas. Generally, triomas are formed by fusion of a hybridoma and a lymphocyte (e.g., antibody- secreting B cell) and hybrid hybridomas are formed by fusion of two hybridomas. Each of the fused cells (i.e., hybridomas, lymphocytes) produces a monospecific antibody. However, triomas and hybrid hybridomas can produce an antibody containing antigen-binding sites that recognize different antigens. The supernatants of triomas and hybrid hybridomas can be assayed for bispecific antibody using a suitable assay (e.g., ELISA), and bispecific antibodies can be purified using conventional methods, (see, e.g., U.S. Patent No. 5,959,084 (Ring et al), U.S. Patent No. 5,141,736 (Iwasa et al), U.S. Patent Nos. 4,444,878, 5,292,668, 5,523,210 (all to Paulus et al) and U.S. Patent No. 5,496,549 (Yamazaki et al)). In one embodiment, the invention relates to an isolated cell that produces an antibody or an antigen-binding fragment of the invention. In a particular embodiment, the isolated antibody-producing cell of the invention is an immortalized cell, such as a hybridoma, heterohybridoma, lymphoblastoid cell or a recombinant cell. The antibody-producing cells of the present invention have uses other than for the production of antibodies. For example, the cell of the present invention can be fused with other cells (such as suitably drug-marked human myeloma, mouse myeloma, human-mouse heteromyeloma or human lymphoblastoid cells) to produce, for example, additional hybridomas, and thus provide for the transfer of the genes encoding the antibody. In addition, the cell can be used as a source of nucleic acids encoding the anti-HMGB immunoglobulin chains, which can be isolated and expressed (e.g., upon transfer to other cells using any suitable technique (see e.g., Cabilly et al, U.S. Patent No. 4,816,567, Winter, U.S. Patent No. 5,225,539)). For instance, clones comprising a sequence encoding a rearranged anti-HMGB light and/or heavy chain can be isolated (e.g., by PCR). In addition, cDNA libraries can be prepared from mRNA isolated from an appropriate cell line, and cDNA clones encoding an anti- HMGB immunoglobulin chain(s) can be isolated. Thus, nucleic acids encoding the heavy and/or light chains of the antibodies, or portions thereof, can be obtained and used for the production of the specific immunoglobulin, immunoglobulin chain, or variants thereof (e.g., humanized immunoglobulins) in a variety of host cells or in an in vitro translation system. For example, the nucleic acids, including cDNAs, or derivatives thereof encoding variants such as a humanized immunoglobulin or immunoglobulin chain, can be placed into suitable prokaryotic or eukaryotic vectors (e.g., expression vectors) and introduced into a suitable host cell by an appropriate method (e.g., transformation, transfection, electroporation, infection), such that the nucleic acid is operably linked to one or more expression control elements (e.g., in the vector or integrated into the host cell genome), to produce a recombinant antibody-producing cell. Thus, in certain embodiments, the invention is a nucleic acid that encodes an antibody or antigen-binding fragment of the invention. In other embodiments, the invention is a vector that comprises a nucleic acid encoding an antibody or antigen-binding fragment of the invention.

HMGB Polypeptides, HMGB A boxes and HMGB B boxes As described, in one embodiment the invention is an antibody or antigen- binding fragment thereof that binds to an HMGB polypeptide. As used herein, an "HMGB polypeptide" is a polypeptide that has at least 60%, more preferably, at least 70%, 75%, 80%, 85%, or 90%, and most preferably at least 95% sequence identity, to a sequence selected from the group consisting of SEQ LD NO:l, SEQ JD NO:18 and SEQ ID NO:74 (as determined, for example, using the BLAST program and parameters described herein). In one embodiment, the HMGB polypeptide increases inflammation and/or increases release of a proinflammatory cytokine from a cell. In another embodiment, the HMGB polypeptide has one of the above biological activities. Typically, the HMGB polypeptide has both of the above biological activities. The term "polypeptide" refers to a polymer of amino acids, and not to a specific length; thus, peptides, oligopeptides and proteins are included within the definition of a polypeptide. In one embodiment, the HMGB polypeptide is a mammalian HMGB polypeptide, for example, a mammalian HMGB polypeptide (e.g., a human HMGBl polypeptide). In another embodiment, the HMGB polypeptide contains a B box DNA binding domain and/or an A box DNA binding domain and/or an acidic carboxyl terminus as described herein. Other examples of HMGB polypeptides are described in GenBank Accession Numbers AAA64970, AAB08987, P07155, AAA20508, S29857, P09429, NP_002119, CAA31110, S02826, U00431, X67668, NP_005333, NM_016957, and J04179, the entire teachings of which are incorporated herein by reference. Additional examples of HMGB polypeptides include, but are not limited to mammalian HMGl ((HMGBl) as described, for example, in GenBank Accession Number U51677), HMG2 ((HMGB2) as described, for example, in GenBank Accession Number M83665), HMG-2A ((HMGB3, HMG-4) as described, for example, in GenBank Accession Numbers NM_005342 and NP_005333), HMG14 (as described, for example, in GenBank Accession Number P05114), HMGl 7 (as described, for example, in GenBank Accession Number X13546), HMGl (as described, for example, in GenBank Accession Number L17131), and HMGY (as described, for example, in GenBank Accession Number M23618); nonmammalian HMG TI (as described, for example, in GenBank Accession Number X02666) and HMG T2 (as described, for example, in GenBank Accession Number L32859) (rainbow trout); HMG-X (as described, for example, in GenBank Accession Number D30765) (Xenopus); HMG D (as described, for example, in GenBank Accession Number X71138) and HMG Z (as described, for example, in GenBank Accession Number X71139) (Drosophila); NHPIO protein (HMG protein homolog NHP 1) (as described, for example, in GenBank Accession Number¹ Z48008) (yeast); non-histone chromosomal protein (as described, for example, in GenBank Accession Number O00479) (yeast); HMG 1/ 2 like protein (as described, for example, in GenBank Accession Number Zl 1540) (wheat, maize, soybean); upstream binding factor (UBF-1) (as described, for example, in GenBank Accession Number X53390); PMS1 protein homolog 1 (as described, for example, in GenBank Accession Number U13695); single-strand recognition protein (SSRP, structure-specific recognition protein) (as described, for example, in GenBank Accession Number M86737); the HMG homolog TDP-1 (as described, for example, in GenBank Accession Number M74017); mammalian sex-determining region Y protein (SRY, testis-determining factor) (as described, for example, in GenBank Accession Number X53772); fungal proteins: mat-1 (as described, for example, in GenBank Accession Number AB009451), ste 11 (as described, for example, in GenBank Accession Number X53431) and Mc 1; SOX 14 (as described, for example, in GenBank Accession Number AF107043) (as well as SOX 1 (as described, for example, in GenBank Accession Number Y13436), SOX 2 (as described, for example, in GenBank Accession Number Z31560), SOX 3 (as described, for example, in GenBank Accession Number X71135), SOX 6 (as described, for example, in GenBank Accession Number AF309034), SOX 8 (as described, for example, in GenBank Accession Number AF226675), SOX 10 (as described, for example, in GenBank Accession Number AJ001183), SOX 12 (as described, for example, in GenBank Accession Number X73039) and SOX 21 (as described, for example, in GenBank Accession Number AFl 07044)); lymphoid specific factor (LEF-1) (as described, for example, in GenBank Accession Number X58636); T-cell specific transcription factor (TCF-1) (as described, for example, in GenBank Accession Number X59869); MTT1 (as described, for example, in GenBank Accession Number M62810); and SPIOO-HMG nuclear autoantigen (as described, for example, in GenBank Accession Number U36501). Other examples of HMGB proteins are polypeptides encoded by HMGB nucleic acid sequences having GenBank Accession Numbers NG_000897 (HMGILIO) (and in particular by nucleotides 658-1305 of NG_000897); AF076674 (HMG1L1) (and in particular by nucleotides 1-633 of AF076674; AF076676 (HMG1L4) (and in particular by nucleotides 1-564 of AF076676); AC010149 (HMG sequence from BAC clone RP11-395 A23) (and in particular by nucleotides 75503-76117 of AC010149); AF165168 (HMG1L9) (and in particular by nucleotides 729-968 of AF165168); XM_063129 (LOC122441) (and in particular by nucleotides 319-558 of XM_063129); XM_066789 (LOC139603) (and in particular by nucleotides 1-258 ofXM_066789); andAF165167 (HMG1L8) (and in particular by nucleotides 456-666 of AF165167). The antibodies and antigen-binding fragments of the invention bind to an HMGB polypeptide (e.g., one or more of the HMGB polypeptides listed above). In one embodiment, the antibody or antigen-binding fragment thereof binds to a vertebrate HMGB polypeptide. In another embodiment, the antibody or antigen- binding fragment thereof binds to a mammalian HMGB polypeptide (e.g., rat HMGB, mouse HMGB, human HMGB). In still another embodiment, the antibody or antigen-binding fragment thereof binds to a mammalian HMGB 1 polypeptide (e.g., rat HMGBl, mouse HMGBl, human HMGBl). In a particular embodiment, the antibody or antigen-binding fragment thereof binds to a human HMGBl polypeptide (e.g., the human HMGBl polypeptide depicted as SEQ ID NO:l or SEQ ID NO:74). The compositions and methods of the present invention also feature antibodies to the high mobility group B (HMGB) A box. In one embodiment, the antibody or antigen-binding fragment thereof binds to an HMGB A box but does not specifically bind to non-A box epitopes of HMGB. In another embodiment, the antibody or antigen-binding fragment thereof binds to a vertebrate HMGB A box but does not specifically bind to non-A box epitopes of HMGB. In another embodiment, the antibody or antigen-binding fragment thereof binds to a mammalian (e.g., human, rat, mouse) HMGB A box but does not specifically bind to non-A box epitopes of HMGB. In still another embodiment, the antibody or antigen-binding fragment thereof binds to the A box of a HMGBl polypeptide (e.g., a mammalian HMGBl polypeptide (e.g., human HMGBl, rat HMGBl, mouse HMGBl)) but does not specifically bind to non-A box epitopes of HMGB 1. As used herein, an "HMGB A box", also referred to herein as an "A box" or "HMG A box", is a protein or polypeptide that has at least 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95%, sequence identity to an HMGB A box (e.g., an HMGB A box described herein). In one embodiment, the HMGB A box has one or more of the following biological activities: inhibiting inflammation mediated by HMGB and/or inhibiting release of a proinflammatory cytokine from a cell (see, e.g., PCT Publication No. WO 02/092004; the entire teachings of which are incorporated herein by reference). In one embodiment, the HMGB A box polypeptide has one of the above biological activities. Typically, the HMGB A box polypeptide has both of the above biological activities. In one embodiment, the A box has at least 50%, 60%, 70%, 75%, 80%, 85%, 90%, or 95%, sequence identity to the A box depicted in FIG. 2A (residues 9-85 of SEQ ID NO:2) or FIG. 3 IB (SEQ ID NO:75). In another embodiment, the A box comprises or consists of the amino acid sequence in the corresponding region of an HMGB protein in a mammal. An HMGB A box is also a recombinantly-produced polypeptide having the same amino acid sequence as the A box sequences described herein. iThe HMGB A box is preferably a vertebrate HMGB A box, for example, a mammalian HMGB A box, more preferably, a mammalian HMGBl A box, for example, a human HMGBl A box, and most preferably, the HMGBl A box comprising or consisting of the sequence of the A box depicted in FIG. 2A (residues 9-85 of SEQ ID NO:2) or FIG. 3 IB (SEQ ID NO:75). An HMGB A box often has no more than about 85 amino acids and no fewer than about 4 amino acids. In other embodiments, an HMGB A box can comprise from 10-85 amino acids, 20-85 amino acids, 30-85 amino acids or 40-85 amino acids. Examples of polypeptides having A box sequences within them include, but are not limited to the HMGB polypeptides described above. The A box sequences in such HMGB polypeptides can be determined and isolated using methods described herein, for example, by sequence comparisons to A boxes described herein and testing for biological activity using methods described herein and/or other methods known in the art. Additional examples of HMGB A box polypeptide sequences include the following sequences: PDASVNFSEF SKKCSERWKT MSAKEKGKFE DMAKADKARY EREMKTYJPP KGET (human HMGBl; SEQ ID NO:55); DSSVNFAEF SKKCSERWKT MSAKEKSKFE DMAKSDKARY DREMKNYVPP KGDK (human HMGB2; SEQ ID NO:56); PEVPVNFAEF SKKCSERWKT VSGKEKSKFD EMAKADKVRY DREMKDYGPA KGGK (human HMGB3; SEQ ID NO:57); PDASVNFSEF SKKCSERWKT MSAKEKGKFE DMAKADKARY EREMKTYJPP KGET (HMGILIO; SEQ ID NO:58); SDASVNFSEF SNKCSERWK MSAKEKGKFE DMAKADKTHY ERQMKTYJPP KGET (HMG1L1; SEQ ID NO:59); PDASVNFSEF SKKCSERWKA MSAKDKGKFE DMAKVDKADY EREMKTYIPP KGET (HMG1L4; SEQ ID NO:60); PDASVKFSEF LKKCSETWKT JJFAKEKGKFE DMAKADKAHY EREMKTYIPP KGEK (HMG sequence from BAC clone RP11-395 A23; SEQ ID NO:61); PDASLNFSEF SQKCPETWKT TIAKEKGKFE DMAKADKAHY EREMKTYIPP KGET (HMG1L9; SEQ ID NO:62); PDASVNSSEF SKKCSERWKTMPTKQGKFE DMAKADRAH (HMG1L8; SEQ ID NO:63); PDASVNFSEF SKKCLVRGKT MSAKEKGQFE AMARADKARY EREMKTYIP PKGET (LOCI 22441; SEQ ID NO:64); LDASVSFSEF SNKCSERWKT MSVKEKGKFE DMAKADKACY EREMKIYPYL KGRQ (LOC139603; SEQ ID NO:65); and GKGDPKKPRG KMSSYAFFVQ TCREEHKKKH PDASVNFSEF SKKCSERWKT MSAKEKGKFE

DMAKADKARY EREMKTYIPP KGET (human HMGBl A box; SEQ ID NO:66). The compositions and methods of the present invention also feature antibodies to the high mobility group B (HMGB) B box. In one embodiment, the antibody or antigen-binding fragment thereof binds to an HMGB B box but does not specifically bind to non-B box epitopes of HMGB. In another embodiment, the antibody or antigen-binding fragment thereof binds to a vertebrate HMGB B box but does not specifically bind to non-B box epitopes of HMGB. In another embodiment, the antibody or antigen-binding fragment thereof binds to a mammalian (e.g., human, rat, mouse) HMGB B box but does not specifically bind to non-B box epitopes of HMGB. In still another embodiment, the antibody or antigen-binding fragment thereof binds to the B box of a HMGBl polypeptide (e.g., a mammalian HMGBl polypeptide (e.g., human HMGBl, rat HMGBl, mouse HMGBl)) but does not specifically bind to non-B box epitopes of HMGB 1. As used herein, an "HMGB B box", also referred to herein as a "B box" or "an HMG B box", is a polypeptide that has at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, sequence identity to an HMGBl polypeptide (e.g., an HMGB B box described herein). In one embodiment, the HMGBl box has one or more of the following biological activities: increasing inflammation and/or increasing release of a proinflammatory cytokine from a cell (see, e.g., PCT Publication No. WO 02/092004). In one embodiment, the HMGB B box polypeptide has one of the above biological activities. Typically, the HMGB B box polypeptide has both of the above biological activities. In one embodiment, the HMGB B box has at least 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95%, sequence identity to the B box depicted in FIG. 2B (SEQ ID NO:3) or FIG. 31C (SEQ ID NO:76). In another embodiment, the B box comprises or consists of the amino acid sequence in the corresponding region of an HMGB protein in a mammal. An HMGB B box is also a recombinantly- produced polypeptide having the same amino acid sequence as the B box sequences described herein. The HMGB B box is preferably a vertebrate HMGB B box, for example, a mammalian HMGB B box, more preferably, a mammalian HMGBl B box, for example, a human HMGBl B box, and most preferably, the HMGBl B box comprising or consisting of the sequence of the B box depicted in FIG. 2B (SEQ ID NO:3) or FIG. 31C (SEQ LD NO:76). An HMGB B box often has no more than about 85 amino acids and no fewer than about 4 amino acids. Examples of polypeptides having B box sequences within them include, but are not limited to, the HMGB polypeptides described above. The B box sequences in such polypeptides can be determined and isolated using methods described herein, for example, by sequence comparisons to B boxes described herein and testing for biological activity. Examples of additional HMGB B box polypeptide sequences include the following sequences: FKDPNAPKRP PSAFFLFCSE YRPKTKGEHP GLSIGDVAKK LGEMWNNTAA DDKQPYEKKA AKLKEKYEKD IAAY (human HMGBl; SEQ ID NO:67); KKDPNAPKRP PSAFFLFCSE HRPKIKSEHP GLSIGDTAKK LGEMWSEQSA KDKQPYEQKA AKLKEKYEKD IAAY (human HMGB2; SEQ ID NO:68); FKDPNAPKRL PSAFFLFCSE YRPKTKGEHP GLSIGDVAKK LGEMWNNTAA DDKQPYEKKA AKLKEKYEKD IAAY (HMGILIO; SEQ LD NO:69); FKDPNAPKRP PSAFFLFCSE YHPKIKGEHP GLSIGDVAKK LGEMWNNTAA DDKQPGEKKA AKLKEKYEKD IAAY (HMG1L1; SEQ ID NO:70); FKDSNAPKRP PSAFLLFCSE YCPKJJ GEHP GLPISDVAKK LVEMWNNTFA DDKQLCEKKA AKLKEKYKKD TATY (HMG1L4; SEQ ID NO:71); FKDPNAPKRP PSAFFLFCSE YRPKTKGEHP GLSIGDWKK LAGMWNNTAA ADKQFYEKKA AKLKEKYKKD IAAY (HMG sequence from BAC clone RP11-359A23; SEQ ID NO:72); and

FKDPNAPKRP PSAFFLFCSE YRPKTKGEHP GLSIGDVAKK LGEMWNNTAA DDKQPYEKKA AKLKEKYEKD IAAYRAKGKP D AAKKGVVKA EK (human HMGBl box; SEQ ID NO:73). As described herein, an HMGB polypeptide, an HMGB A box, and an HMGB B box, either naturally occurring or non-naturally occurring, encompass polypeptides that have sequence identity to the HMGB polypeptides, HMGB A boxes, and/or HMGB B boxes, described herein. As used herein, two polypeptides (or a region of the polypeptides) are substantially homologous or identical when the amino acid sequences are at least about 60%, 70%, 75%, 80%, 85%, 90%, or 95% or more, homologous or identical. The percent identity of two amino acid sequences (or two nucleic acid sequences) can be determined by aligning the sequences for optimal comparison purposes (e.g., gaps can be introduced in the sequence of a first sequence). The amino acids or nucleotides at conesponding positions are then compared, and the percent identity between the two sequences is a function of the number of identical positions shared by the sequences (i.e., % identity = # of identical positions/total # of positions x 100). In certain embodiments, the length of the HMGB polypeptide, HMGB A box polypeptide, or HMGB B box polypeptide, aligned for comparison purposes is at least 30%, preferably at least 40%, more preferably at least 60%, and even more preferably at least 70%, 80%, 90%, or 100%, of the length of the reference sequence, for example, the sequences described herein corresponding to an HMGB polypeptide (e.g., SEQ ID NO:l; SEQ JD NO:18, SEQ ID NO:74), an HMGB A box polypeptide (e.g., residues 9-85 of SEQ ID NO:2, SEQ ID NO:75) or an HMGB B box polypeptide (e.g., SEQ ID NO:3, SEQ ID NO:76). The actual comparison of the two sequences can be accomplished by well-known methods, for example, using a mathematical algorithm. A preferred, non-limiting example of such a mathematical algorithm is described in Karlin et al. (Proc. Natl. Acad. Sci. USA, 90:5873-5877 (1993)). Such an algorithm is incorporated into the BLASTN and BLASTX programs (version 2.2) as described in Schaffer et al. (Nucleic Acids Res., 29:2994-3005 (2001)). When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., BLASTN; available at the Internet site for the National Center for Biotechnology Information) can be used. In one embodiment, the database searched is a non-redundant (NR) database, and parameters for sequence comparison can be set at: no filters; Expect value of 10; Word Size of 3; the Matrix is BLOSUM62; and Gap Costs have an Existence of 11 and an Extension of 1. Another non-limiting example of a mathematical algorithm utilized for the comparison of sequences is the algorithm of Myers and Miller, CABIOS (1989). Such an algorithm is incorporated into the ALIGN program (version 2.0), which is part of the GCG (Accelrys, San Diego, California) sequence alignment software package. When utilizing the ALIGN program for comparing amino acid sequences, a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4 can be used. Additional algorithms for sequence analysis are known in the art and include ADVANCE and ADAM as described in Torellis and Robotti (Comput. Appl. Biosci., 10: 3-5, 1994); andFASTA described in Pearson and Lipman (Proc. Natl. Acad. Sci USA, 85: 2444-2448, 1988). In another embodiment, the percent identity between two amino acid sequences can be accomplished using the GAP program in the GCG software package (Accelrys, San Diego, California) using either a Blossom 63 matrix or a PAM250 matrix, and a gap weight of 12, 10, 8, 6, or 4, and a length weight of 2, 3, or 4. In yet another embodiment, the percent identity between two nucleic acid sequences can be accomplished using the GAP program in the GCG software package (Accelrys, San Diego, California), using a gap weight of 50 and a length weight of 3.

Inhibiting Release of Proinflammatory Cytokines and Methods of Treatment hi one embodiment, the present invention is a method of inhibiting release of a proinflammatory cytokine from a mammalian cell. In one embodiment, the method comprises treating the cell with an antibody or antigen-binding fragment of the present invention. Suitable antibodies or antigen-binding fragments are those described herein and include, e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb, an antibody having the epitopic specificity of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGB 1 mAb and/or 2E11 HMGB 1 mAb, an antibody that can compete with 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide, and an antigen-binding fragment of any of the foregoing. As used herein, a "cytokine" is a soluble protein or peptide that is naturally produced by mammalian cells and that regulates immune responses and mediates cell-cell interactions. Cytokines can, either under normal or pathological conditions, modulate the functional activities of individual cells and tissues. A proinflammatory cytokine is a cytokine that is capable of causing one or more of the following physiological reactions associated with inflammation or inflammatory conditions: vasodilation, hyperemia, increased permeability of vessels with associated edema, accumulation of granulocytes and mononuclear phagocytes, and deposition of fibrin. In some cases, the proinflammatory cytokine can also cause apoptosis. For example, in chronic heart failure, it has been shown that TNF stimulates cardiomyocyte apoptosis (?ul]όά, Ann. Med. 29:339-343 (1997); and Tsutsui, et al, Immunol. Rev. 174:192-209 (2000)). Nonlimiting examples of proinflammatory cytokines are tumor necrosis factor (TNF), interleukin (TL)-lα, IL-lβ, JL-6, E -8, JX-18, interferon γ, HMG-1, platelet-activating factor (PAF), and macrophage migration inhibitory factor (MIF). In another embodiment, the invention is a method of treating a condition in a subject, wherein the condition is characterized by activation of an inflammatory cytokine cascade comprising administering to the subject an antibody or antigen- binding fragment of the present invention. Suitable antibodies or antigen-binding fragments are those described herein and include, e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb, an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb, an antibody that can compete with 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide, and an antigen-binding fragment of any of the foregoing. In one embodiment, the method of treatment comprises administering to a subject an effective amount of an antibody or antigen-binding fragment of the invention. As used herein, an "effective amount" or "therapeutically effective amount" is an amount sufficient to prevent or decrease an inflammatory response, and/or to ameliorate and/or decrease the longevity of symptoms associated with an inflammatory response. The amount of the composition of the invention that will be effective in the treatment, prevention or management of a particular condition can be determined, for example, by administering the composition to an animal model such as, e.g., the animal models disclosed herein and/or known to those skilled in the art. In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. Selection of the preferred effective dose can be determined (e.g., via clinical trials) by a skilled artisan based upon the consideration of several factors that are known to one of ordinary skill in the art. Such factors include, e.g., the condition or conditions to be treated, the severity of the subject's symptoms, the choice of antibody or antigen-binding fragment to be administered, the subject's age, the subject's body mass, the subject's immune status, the response of the individual subject, and other factors known by the skilled artisan to reflect the accuracy of administered pharmaceutical compositions. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness of the condition, and should be decided according to the judgment of the practitioner and each subject's circumstances. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. For example, as exemplified herein, using an in vivo cecal ligation and puncture (CLP) assay, a dose response assay for anti-HMGBl monoclonal antibody 6E6 HMGBl mAb (at doses of 1 μg/mouse, 10 μg/mouse or 100 μg/mouse) was conducted (FIG. 16). For antibodies, the dosage administered to a subject (e.g., a human patient) is typically 0.1 mg/kg to 100 mg/kg of the subject's body weight. Preferably, the dosage administered to a subject is between 0.1 mg/kg and 20 mg/kg of the subject's body weight, more preferably 1 mg/kg to 10 mg/kg of the subject's body weight. In certain embodiments of the invention, the dosage is at least lmg/kg, or at least 5 mg/kg, or at least 10 mg/kg, or at least 50 mg/kg, or at least 100 mg/kg, or at least 150 mg/kg, of the subject's body weight. Generally, human and humanized antibodies have a longer half-life within the human body than antibodies from other species due to the immune response to foreign polypeptides. Thus, lower dosages of human antibodies and less frequent administration is often possible. For example, an effective amount of an antibody can range from about 0.01 mg/kg to about 5 or 10 mg/kg administered daily, weekly, biweekly or monthly. Methods for determining whether an antibody or antigen-binding fragment inhibits an inflammatory condition are known to one skilled in the art. For example, inhibition of the release of a proinflammatory cytokine from a cell can be measured according to methods known to one skilled in the art. For example, as described and exemplified herein, TNF release from a cell can be measured using a standard murine fibroblast L929 (ATCC, American Type Culture Collection, Rockville, Maryland) cytotoxicity bioassay (Bianchi et al, Journal of Experimental Medicine 55:927-936 (1996)) with the minimum detectable concentration of 30 pg/ml. The L929 cytotoxicity bioassay is carried out as follows. RAW 264.7 cells are cultured in RPMI 1640 medium (Life Technologies, Grand Island, New York) supplemented with 10% fetal bovine serum (Gemini, Catabasas, California), and penicillin and streptomycin (Life Technologies). Polymyxin (Sigma, St. Louis, Missouri) is added at 100 units/ml to suppress the activity of any contaminating LPS. Cells are incubated with the antibodies described herein in Opti-MEM I medium for 8 hours, and conditioned supernatants (containing TNF that has been released from the cells) are collected. TNF that is released from the cells is measured by a standard murine fibroblast L929 (ATCC) cytotoxicity bioassay (Bianchi et al, supra) with the minimum detectable concentration of 30 pg/ml. Recombinant mouse TNF can be obtained from R & D Systems Inc. (Minneapolis, Minnesota) and used as a control in these experiments. Methods for measuring release of other cytokines from cells are also known in the art. An inflammatory condition that is suitable for the methods of treatment described herein can be one in which the inflammatory cytokine cascade is activated. In one embodiment,- the inflammatory cytokine cascade causes a systemic reaction, such as with endotoxic shock. In another embodiment, the inflammatory condition is mediated by a localized inflammatory cytokine cascade, as in rheumatoid arthritis. Nonlimiting examples of inflammatory conditions that can be usefully treated using the antibodies and antigen-binding fragments of the present invention include, e.g., diseases involving the gastrointestinal tract and associated tissues (such as ileus, appendicitis, peptic, gastric and duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute and ischemic colitis, diverticulitis, epiglottitis, achalasia, cholangitis, cholecystitis, coeliac disease, hepatitis, Crohn's disease, enteritis, and Whipple's disease); systemic or local inflammatory diseases and conditions (such as asthma, allergy, anaphylactic shock, immune complex disease, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, hyperpyrexia, eosinophilic granuloma, granulomatosis, and sarcoidosis); diseases involving the urogenital system and associated tissues (such as septic abortion, epididymitis, vaginitis, prostatitis, and urethritis); diseases involving the respiratory system and associated tissues (such as bronchitis, emphysema, rhimtis, cystic fibrosis, pneumonitis, adult respiratory distress syndrome, pneumoultramicroscopicsilicovolcanoconiosis, alvealitis, bronchiolitis, pharyngitis, pleurisy, and sinusitis); diseases arising from infection by various viruses (such as influenza, respiratory syncytial virus, HIV, hepatitis B virus, hepatitis C virus and herpes), bacteria (such as disseminated bacteremia, Dengue fever), fungi (such as candidiasis) and protozoal and multicellular parasites (such as malaria, filariasis, amebiasis, and hydatid cysts); dermatological diseases and conditions of the skin (such as burns, dermatitis, dermatomyositis, sunburn, urticaria warts, and wheals); diseases involving the cardiovascular system and associated tissues (such as stenosis, restenosis, vasulitis, angiitis, endocarditis, arteritis, atherosclerosis, thrombophlebitis, pericarditis, congestive heart failure, myocarditis, myocardial ischemia, periarteritis nodosa, and rheumatic fever); diseases involving the central or peripheral nervous system and associated tissues (such as Alzheimer's disease, meningitis, encephalitis, multiple sclerosis, cerebral infarction, cerebral embolism, Guillame-Barre syndrome, neuritis, neuralgia, spinal cord injury, paralysis, and uveitis); diseases of the bones, joints, muscles and connective tissues (such as the various arthritides and arthralgias, osteomyelitis, fasciitis, Paget's disease, gout, periodontal disease, rheumatoid arthritis, and synovitis); other autoimmune and inflammatory disorders (such as myasthenia gravis, thryoiditis, systemic lupus erythematosus, Goodpasture's syndrome, Behcets's syndrome, allograft rejection, graft- versus-host disease, Type I diabetes, ankylosing spondylitis, Berger' s disease, and Retier's syndrome); as well as various cancers, tumors and proliferative disorders (such as Hodgkins disease); and, in any case the inflammatory or immune host response to any primary disease. In one embodiment, the condition is selected from the group consisting of sepsis, allograft rejection, arthritis (e.g., rheumatoid arthritis), asthma, atherosclerosis, restenosis, lupus, adult respiratory distress syndrome, chronic obstructive pulmonary disease, psoriasis, pancreatitis, peritonitis, bums, myocardial ischemia, organic ischemia, reperfusion ischemia, Behcet's disease, graft versus host disease, Crohn's disease, ulcerative colitis, ileus, multiple sclerosis, and cachexia. In another embodiment, the condition is selected from the group consisting of sepsis, arthritis (e.g., rheumatoid arthritis), asthma, lupus, psoriasis, inflammatory bowel disease and Crohn's disease. Preferably the antibodies and antigen-binding fragments are administered to a patient in need thereof in an amount sufficient to inhibit release of proinflammatory cytokine from a cell and/or to treat an inflammatory condition. In one embodiment, release of the proinflammatory cytokine is inhibited by at least 10%, 20%, 25%, 50%, 75%, 80%, 90%, or 95%, as assessed using methods described herein or other methods known in the art. The terms "therapy", "therapeutic" and "treatment", as used herein, refer to ameliorating symptoms associated with a disease or condition, for example, an inflammatory disease or an inflammatory condition, including preventing or delaying the onset of the disease symptoms, and/or lessening the severity or frequency of symptoms of the disease or condition. The terms "subject" and "individual" are defined herein to include animals such as mammals, including but not limited to, primates, cows, sheep, goats, horses, dogs, cats, rabbits, guinea pigs, rats, mice or other bovine, ovine, equine, canine, feline, rodent, or murine species, h one embodiment, the animal is a human. In one embodiment, an excipient can be included with the antibodies and antigen-binding fragments of the invention. The excipient can be selected based on the expected route of administration of the antibodies or antigen-binding fragments in therapeutic applications. The route of administration of the composition depends on the condition to be treated. For example, intravenous injection may be prefened for treatment of a systemic disorder such as endotoxic shock, and oral administration may be preferred to treat a gastrointestinal disorder such as a gastric ulcer. As described above, the dosage of the antibody or antigen-binding fragment to be administered can be determined by the skilled artisan without undue experimentation in conjunction with standard dose-response studies. Depending on the condition, the antibody or antigen-binding fragment can be administered orally, parenterally, intranasally, vaginally, rectally, lingually, sublingually, bucally, intrabucally and transdermally to the patient. Accordingly, antibodies or antigen-binding fragments designed for oral, lingual, sublingual, buccal and intrabuccal administration can be made without undue experimentation by means well known in the art, for example, with an inert diluent and/or edible carrier. The antibodies or antigen-binding fragments may be enclosed in gelatin capsules or compressed into tablets. For the purpose of oral therapeutic admi stration, the antibodies or antigen-binding fragments of the present invention may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gums, and the like. Tablets, pills, capsules, troches, and the like, may also contain binders, recipients, disintegrating agent, lubricants, sweetening agents, and flavoring agents. Some examples of binders include microcrystalline cellulose, gum tragacanth, and gelatin. Examples of excipients include starch and lactose. Some examples of disintegrating agents include alginic acid, com starch, and the like. Examples of lubricants include magnesium stearate and potassium stearate. An example of a glidant is colloidal silicon dioxide. Some examples of sweetening agents include sucrose, saccharin, and the like. Examples of flavoring agents include peppermint, methyl salicylate, orange flavoring, and the like. Materials used in preparing these various compositions should be pharmaceutically pure and non-toxic in the amounts used. The antibodies and antigen-binding fragments of the present invention can be administered parenterally such as, for example, by intravenous, intramuscular, intrathecal or subcutaneous injection. Parenteral administration can be accomplished by incorporating the antibodies and antigen-binding fragments of the present invention into a solution or suspension. Such solutions or suspensions may also include sterile diluents, such as water for injection, saline solution, bacteriostatic saline (saline containing about 0.9% mg/ml benzyl alcohol), phosphate-buffered saline (referred to herein as PBS), Hank's solution, Ringer's- lactate, fixed oils, polyethylene glycols, glycerine, propylene glycol, and other synthetic solvents. Parenteral formulations may also include antibacterial agents (e.g., benzyl alcohol, methyl parabens), antioxidants (e.g., ascorbic acid, sodium bisulfite), and chelating agents (e.g., EDTA). Buffers, such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride and dextrose, may also be added. The parenteral preparation can be enclosed in ampules, disposable syringes, or multiple dose vials made of glass or plastic. Rectal administration includes administering the antibodies and antigen- binding fragments into the rectum or large intestine. This can be accomplished using suppositories or enemas. Suppository formulations can be made by methods known in the art. For example, suppository formulations can be prepared by heating glycerin to about 120°C, dissolving the antibody or antigen-binding fragment in the glycerin, mixing the heated glycerin, after which purified water may be added, and pouring the hot mixture into a suppository mold. Transdermal administration includes percutaneous absorption of the antibody or antigen-binding fragment through the skin. Transdermal formulations include patches, ointments, creams, gels, salves, and the like. The antibodies and antigen-binding fragments of the present invention can be administered nasally to a subject. As used herein, nasally administering or nasal administration, includes administering the antibodies or antigen-binding fragments to the mucous membranes of the nasal passage or nasal cavity of the subject. Pharmaceutical compositions for nasal administration of an antibody or antigen- binding fragment include therapeutically effective amounts of the antibody or antigen-binding fragment. Well-known methods for nasal administration include, for example, as a nasal spray, nasal drop, suspension, gel, ointment, cream, or powder. Administration of the antibody or antigen-binding fragment may also take place using a nasal tampon or nasal sponge. As described above, a variety of routes of administration are possible including, for example, oral, dietary, topical, transdermal, rectal, parenteral (e.g., intravenous, intraarterial, intramuscular, subcutaneous, intradermal injection), and inhalation (e.g., intrabronchial, intranasal, oral inhalation, intranasal drops). Administration can be local or systemic as indicated. The preferred mode of administration can vary depending upon the antibody or antigen-binding fragment to be administered and the particular condition (e.g., disease) being treated, however, oral or parenteral administration is generally preferred. If desired, the antibodies or antigen-binding fragments described herein can be administered with one or more additional agents (e.g., agents used to treat an inflammatory condition). The antibodies or antigen-binding fragments thereof and additional agent(s) can be present in a single composition or administered as separate compositions. If administered as separate compositions, the antibodies or antigen-binding fragments thereof and additional agent(s) can be co-administered or administered separately. hi one embodiment, the antibodies or antigen-binding fragments of the invention are administered with an anti-inflammatory agent. Such agents are known to one of skill in the art. hi one embodiment, the agent is an antagonist of an early sepsis mediator. As used herein, an early sepsis mediator is a proinflammatory cytokine that is released from cells soon (i.e., within 30-60 min.) after induction of an inflammatory cytokine cascade (e.g., exposure to LPS). Nonlimiting examples of these cytokines are JJL-lα, IL-lβ, IL-6, PAF, and MTF. Also included as early sepsis mediators are receptors for these cytokines (for example, tumor necrosis factor receptor type 1) and enzymes required for production of these cytokines, for example, interleukin-lβ converting enzyme). Antagonists of any early sepsis mediator, now known or later discovered, can be useful for these embodiments by further inhibiting an inflammatory cytokine cascade. Nonlimiting examples of antagonists of early sepsis mediators are antisense compounds that bind to the mRNA of the early sepsis mediator, preventing its expression (see, e.g., Ojwang et al, Biochemistry 55:6033-6045 (1997); Pampfer et al, Biol. Reprod. 52:1316-1326 (1995); U.S. Patent No. 6,228,642; Yahata et al, Antisense Nucleic Acid Drug Dev. (5:55-61 (1996); and Taylor et al, Antisense Nucleic Acid Drug Dev. 8: 199-205 (1998)), ribozymes that specifically cleave the mRNA of the early sepsis mediator (see, e.g., Leavitt et al, Antisense Nucleic Acid DrugDev. 70:409-414 (2000); Kisich et al, J. Immunol 163(4):200S-2016 (1999); and Hendrix et al, Biochem. J. 314 (Pt. 2):655-66\ (1996)), and antibodies that bind to the early sepsis mediator and inhibit their action (see, e.g., Kam and Targan, Expert Opin. Pharmacother. 1:615-622 (2000); Nagahira et al, J. Immunol. Methods 222:83-92 (1999); Lavine et al, J. Cereb. Blood Flow Metab. 18:52-58 (1998); and Holmes et al, Hybridoma 19:363-367 (2000)). An antagonist of an early sepsis mediator, now known or later discovered, is envisioned as within the scope of the invention. The skilled artisan can determine the amount of early sepsis mediator to use for inhibiting any particular inflammatory cytokine cascade without undue experimentation with routine dose-response studies. Other agents that can be administered with the antibodies and antigen- binding fragments of the invention include, e.g., Vitaxin™ and other antibodies targeting vβ3 integrin (see, e.g., U.S. Patent No. 5,753,230, PCT Publication Nos. WO 00/78815 and WO 02/070007; the entire teachings of all of which are incorporated herein by reference) and anti-IL-9 antibodies (see, e.g., PCT

Publication No. WO 97/08321; the entire teachings of which are incorporated herein by reference). In one embodiment, the antibodies and antigen-binding fragments of the invention are administered with inhibitors of TNF biological activity e.g., inhibitors of TNF- biological activity). Such inhibitors of TNF activity include, e.g., peptides, proteins, synthesized molecules, for example, synthetic organic molecules, naturally-occurring molecule, for example, naturally occurring organic molecules, nucleic acid molecules, and components thereof. Preferred examples of agents that inhibit TNF biological activity include infliximab (Remicade; Centocor, Inc., Malvem, Pennsylvania), etanercept (Immunex; Seattle, Washington), adalimumab (D2E7; Abbot Laboratories, Abbot Park Illinois), CDP870 (Pharmacia Corporation; Bridgewater, New Jersey) CDP571 (Celltech Group pic, United Kingdom), Lenercept (Roche, Switzerland), and Thalidomide. In certain embodiments, the present invention is directed to a composition comprising the antibody or antigen-binding fragments described herein, in a pharmaceutically-acceptable excipient. As described above, the excipient included with the antibody or antigen-binding fragment in these compositions is selected based on the expected route of administration of the composition. Suitable pharmaceutically-acceptable excipients include those described above and known to those of skill in the art. In one embodiment, the invention is directed to aptamers of HMGB (e.g., aptamers of HMGBl). As is known in the art, aptamers are macromolecules composed of nucleic acid (e.g., RNA, DNA) that bind tightly to a specific molecular target (e.g., an HMGB protein, an HMGB box (e.g., an HMGB A box, an HMGB B box), an HMGB polypeptide and/or an HMGB epitope as described herein). A particular aptamer may be described by a linear nucleotide sequence and is typically about 15-60 nucleotides in length. The chain of nucleotides in an aptamer form intramolecular interactions that fold the molecule into a complex three-dimensional shape, and this three-dimensional shape allows the aptamer to bind tightly to the surface of its target molecule. Given the extraordinary diversity of molecular shapes that exist within the universe of all possible nucleotide sequences, aptamers may be obtained for a wide array of molecular targets, including proteins and small molecules. In addition to high specificity, aptamers have very high affinities for their targets (e.g., affinities in the picomolar to low nanomolar range for proteins). Aptamers are chemically stable and can be boiled or frozen without loss of activity. Because they are synthetic molecules, they are amenable to a variety of modifications, which can optimize their function for particular applications. For example, aptamers can be modified to dramatically reduce their sensitivity to degradation by enzymes in the blood for use in in vivo applications. In addition, aptamers can be modified to alter their biodistribution or plasma residence time. Selection of apatmers that can bind HMGB or a fragment thereof (e.g.,

HMGBl or a fragment thereof) can be achieved through methods known in the art. For example, aptamers can be selected using the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) method (Tuerk, C, and Gold, L., Science 249:505-510 (1990)). In the SELEX method, a large library of nucleic acid molecules (e.g., 10¹⁵ different molecules) is produced and/or screened with the target molecule (e.g., an HMGB protein, an HMGB box (e.g., an HMGB A box, an HMGB B box), an HMGB polypeptide and/or an HMGB epitope as described herein). The target molecule is allowed to incubate with the library of nucleotide sequences for a period of time. Several methods, known in the art, can then be used to physically isolate the aptamer target molecules from the unbound molecules in the mixture, which can be discarded. The aptamers with the highest affinity for the target molecule can then be purified away from the target molecule and amplified enzymatically to produce a new library of molecules that is substantially enriched for aptamers that can bind the target molecule. The enriched library can then be used to initiate a new cycle of selection, partitioning, and amplification. After 5-15 cycles of this iterative selection, partitioning and amplification process, the library is reduced to a small number of aptamers that bind tightly to the target molecule. Individual molecules in the mixture can then be isolated, their nucleotide sequences determined, and their properties with respect to binding affinity and specificity measured and compared. Isolated aptamers can then be further refined to eliminate any nucleotides that do not contribute to target binding and/or aptamer stmcture, thereby producing aptamers truncated to their core binding domain. See Jayasena, S.D. Clin. Chem. 45:1628-1650 (1999) for review of aptamer technology; the entire teachings of which are incorporated herein by reference). i particular embodiments, the aptamers of the invention have the binding specificity and/or functional activity described herein for the antibodies of the invention. Thus, for example, in certain embodiments, the present invention is drawn to aptamers that have the same or similar binding specificity as described herein for the antibodies of the invention (e.g., binding specificity for a vertebrate HMGB polypeptide, fragment of a vertebrate HMGB polypeptide (e.g., HMGB A box, HMGB B box), epitopic region of a vertebrate HMGB polypeptide (e.g., epitopic region of HMGBl that is bound by one or more of the antibodies of the invention)), hi particular embodiments, the aptamers of the invention can bind to an HMGB polypeptide or fragment thereof and inhibit one or more functions of the HMGB polypeptide. As described herein, function of HMGB polypeptides include, e.g., increasing inflammation, increasing release of a proinflammatory cytokine from a cell, binding to RAGE, binding to TLR2, chemoattraction In a particular embodiment, the aptamer binds HMGBl (e.g., human HMGBl (e.g., as depicted in SEQ ID NO:l or SEQ ID NO:74)) or a fragment thereof (e.g., A box (e.g., residues 9-85 of SEQ ID NO:2, SEQ LD NO:75), B box (e.g., SEQ ID NO:3, SEQ ID NO:76), HMGBl antibody binding epitope as described herein) and inhibits one or more functions of the HMGB polypeptide (e.g., inhibits release of a proinflammatory cytokine from a vertebrate cell treated with HMGB).

Methods of Diagnosis and/or Prognosis In another embodiment, the invention further provides diagnostic and/or prognostic methods for detecting a vertebrate high mobility group box (HMGB) polypeptide in a sample. In one embodiment of the method, a sample is contacted with an antibody or antigen-binding fragment of the present invention, under conditions suitable for binding of the antibody or fragment to an HMGB polypeptide present in the sample. The method further comprises detecting antibody-HMGB complexes or antigen-bmding fragment-HMGB complexes, wherein detection of antibody-HMGB complexes or antigen-binding fragment-HMGB complexes is indicative of the presence of an HMGB polypeptide in the sample. Suitable antibodies or antigen-binding fragments for use in these methods include those described herein, e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2G7 HMGBl mAb, an antigen-binding fragment of any of the foregoing. In another embodiment, the antibody or antigen-binding fragment comprises a detectable label. Labels suitable for use in detection of a complex between an HMGB polypeptide (e.g., a mammalian HMGB polypeptide) and an antibody or antigen-binding fragment include, for example, a radioisotope, an epitope label (tag), an affinity label (e.g., biotin, avidin), a spin label, an enzyme, a fluorescent group or a chemilummescent group. As described, the antibodies and antigen-binding fragments described herein can be used to detect or measure expression of an HMGB polypeptide. For example, antibodies of the present invention can be used to detect or measure an HMGB polypeptide in a biological sample (e.g., cells, tissues or body fluids from an individual such as blood, serum, leukocytes (e.g., activated T lymphocytes), bronchoalveolar lavage fluid, saliva, bowel fluid, synovial fluid, biopsy specimens). In one embodiment, the sample is blood or serum. For example, a sample (e.g., tissue and/or fluid) can be obtained from an individual and a suitable assay can be used to assess the presence or amount of an HMGB polypeptide. Suitable assays include immunological and immunochemical methods such as flow cytometry (e.g., FACS analysis) and inimunosorbent assays, including enzyme-linked immunosorbent assays (ELISA), radioimmunoassay (RIA), chemiluminescence assays, immunoblot (e.g., western blot), immunocytochemistry and immunohistology. Generally, a sample and an antibody or antigen-binding fragment of the present invention are combined under conditions suitable for the formation of a complex between an HMGB polypeptide and the antibody or antigen-binding fragment thereof, and the formation of said complex is assessed (directly or indirectly). In one embodiment, diagnosis and/or prognosis is done using ELISA and/or western blot analysis . As in known in the art, the presence of an increased level of an HMGB polypeptide (e.g., HMGBl) in a sample (e.g., a tissue sample) obtained from an individual can be a diagnostic and/or prognostic indicator for monitoring the severity and predicting the likely clinical course of sepsis for a subject exhibiting symptoms associated with conditions characterized by activation of the inflammatory cascade (see U.S. Patent No. 6,303,321, the entire teachings of which are incorporated herein by reference). Thus, in one embodiment, the antibodies and antigen-binding fragments of the invention can be used in diagnostic and prognostic methods for monitoring the severity and/or predicting the likely clinical course of an inflammatory condition associated with HMGB expression (e.g., the conditions described herein). In certain embodiments, the diagnostic and/or prognostic methods comprise measuring the concentration of HMGB in a sample, preferably a serum sample, and comparing that concentration to a standard for HMGB representative of a normal concentration range of HMGB in a like sample, whereby higher levels of HMGB are indicative of poor prognosis or the likelihood of toxic reactions. The diagnostic method may also be applied to other tissue or fluid compartments such as cerebrospinal fluid or urine. In another embodiment, the invention is a test kit for use in detecting the presence of a vertebrate high mobility group box (HMGB) polypeptide or portion thereof in a sample. Such test kits can comprise, e.g., an antibody or antigen-binding fragment of the invention and one or more ancillary reagents suitable for detecting the presence of a complex between the antibody or antigen-binding fragment and an HMGB polypeptide or portion thereof. The antibody and antigen-binding fragments of the present invention can be provided in lyophilized form, either alone or in combination with additional antibodies specific for other epitopes. The antibodies or antigen-binding fragments thereof, which can be labeled or unlabeled, can be included in the kits with adjunct ingredients (e.g., buffers, such as Tris (Tris(hydroxymethyl)aminomethane), phosphate and carbonate, stabilizers, excipients, biocides and/or inert proteins, e.g., bovine serum albumin). For example, the antibodies or antigen-bmding fragments can be provided as a lyophilized mixture with the adjunct ingredients, or the adjunct ingredients can be separately provided for combination by the user. Generally these adjunct materials will be present in less than about 5% by weight based on the amount of active antibody, and usually will be present in a total amount of at least about 0.001% by weight based on antibody concentration. Where a second antibody or antigen-binding fragment capable of binding to the anti-HMGB antibody or antigen-binding fragment is employed, such antibody or fragment can be provided in the kit, for instance in a separate vial or container. The second antibody or antigen-binding fragment, if present, is typically labeled, and can be formulated in an analogous manner with the antibody formulations described above. The antibodies, antigen-binding fragments and/or ancillary reagent of the kit can be packaged separately or together within suitable containment means (e.g., bottle, box, envelope, tube). When the kit comprises a plurality of individually packaged components, the individual packages can be contained within a single larger containment means (e.g., bottle, box, envelope, tube). Methods of Screening In another embodiment, the invention is a method of detecting or identifying an agent that binds to an HMGB polypeptide (e.g., a mammalian HMGB polypeptide (e.g., an HMGBl polypeptide)). In one embodiment, the method of detecting or identifying an agent that binds to an HMGB polypeptide is a competitive binding assay in which the ability of a test agent to inhibit the binding of an antibody or antigen-binding fragment of the invention is assessed. For example, the antibody or antigen-binding fragment can be labeled with a suitable label as described herein, and the amount of labeled antibody or antigen-binding fragment required to saturate the HMGB polypeptide present in the assay can be determined. For example, a saturating amount of labeled antibody or antigen-binding fragment and various amounts of a test agent can be contacted with an HMGB polypeptide under conditions suitable for binding, and complex formation determined. In this type of assay, a decrease in the amount of complex formed between the labeled antibody or antigen-binding fragment and HMGB polypeptide indicates that the test agent binds to the HMGB polypeptide. In another embodiment, the HMGB polypeptide can be labeled. Suitable labels for labeling antibodies, antigen-binding fragments and/or HMGB polypeptides include those described above. A variety of agents, such as proteins (e.g., antibodies), peptides, peptidomimetics, small organic molecules, nucleic acids and the like, can be tested for binding to an HMGB polypeptide (e.g., a mammalian HMGB polypeptide (e.g., an HMGBl polypeptide)). According to the method of the present invention, agents can be individually screened or one or more agents can be tested simultaneously. Where a mixture of compounds is tested, the compounds selected by the processes described can be separated (as appropriate) and identified using suitable methods (e.g., sequencing, chromatography). The presence of one or more compounds (e.g., a ligand, inhibitor, promoter) in a test sample can also be determined according to these methods. Agents that bind to an HMGB polypeptide and that are useful in the therapeutic methods described herein can be identified, for example, by screening libraries or collections of molecules, such as, the Chemical Repository of the National Cancer Institute, in assays described herein or using other suitable methods. Libraries, such as combinatorial libraries, of compounds (e.g., organic compounds, recombinant or synthetic peptides, "peptoids", nucleic acids) produced by combinatorial chemical synthesis or other methods can be tested (see e.g., Zuckerman, R.N. et al, J. Med. Chem., 37: 2678-2685 (1994) and references cited therein; see also, Ohlmeyer, M.H.J. et al, Proc. Natl. Acad. Sci. USA 90:10922- 10926 (1993) and DeWitt, S.H. et al, Proc. Natl. Acad. Sci. USA 90:6909-6913 (1993), relating to tagged compounds; Rutter, W.J. et al U.S. Patent No. 5,010,175; Huebner, V.D. et al, U.S. Patent No. 5,182,366; and Geysen, H.M., U.S. Patent No. 4,833,092). Where compounds selected from a library carry unique tags, identification of individual compounds by chromatographic methods is possible.

The present invention will now be illustrated by the following Examples, which is not intended to be limiting in any way. The relevant teachings of all publications cited herein that have not explicitly been incorporated herein by reference, are incorporated herein by reference in their entirety.

Example 1 : Materials and Methods

Generation of monoclonal antibodies to HMGBl BALB/c mice were intraperitoneally immunized with 20 μg of recombinant CBP-Rat HMGBl (CBP linked to amino acids 1-215 of rat HMGBl; nucleotide sequence of CBP-Rat HMGB 1 is depicted as SEQ LD NO:4 and the amino acid sequence is depicted as SEQ ID NO: 5 (see FIGS. 3 A and 3B)) mixed with Freund's adjuvant at two-week intervals for 6 weeks. A final boost of 10 μg of the CBP-Rat HMGBl in PBS was given intravenously after 8 weeks. Four days after the final boost, spleens from the mice were isolated and used for fusion. Fusion was carried out using standard hybridoma technique. The spleen was gently pushed through a cell strainer to obtain a single cell suspension. After extensive washing, spleen cells were mixed with SP2/0 myeloma cells. Polyethylene glycol (PEG) was added slowly, followed by media over a period of five minutes. The cells were washed and resuspended in DMEM containing 20% FCS and HAT, transferred to 96 well plates and incubated at 37°C with 10% CO₂ for 10-14 days. In other experiments, a human HMGBl B box polypeptide (SEQ ID NO:3; FIG. 2B) was used as an immuogen. Five female BALB/c mice were intraperitoneally immunized with 10 μg/injection of HMGBl B box mixed with Freund's adjuvant at three-week intervals. A bleed was obtained from the mice 1 week after each boost. Three weeks after the third boost, a final intravenous injection (10 μg/mouse) of the rat HMGBl B box was given. 72 hours after the final boost, hybridoma fusions were carried out as described above. Hybridomas were cultured in DMEM with 20% FBS, HAT, CondiMed and 1 % pen/strep. Positive clones were identified by taking optical readings and identifying those with readings five times that of background. Antibodies to the CBP-Rat HMGBl and human HMGBl B box were screened by limiting dilution and ELISA. ELISA plates were coated with recombinant HMGBl at 3 μg/ml overnight and blocked with phosphate buffered saline (PBS) supplemented with 1% bovine serum albumin (BSA). Supernatants from the hybridomas were added to the ELISA plates and incubated at room temperature for 30 minutes. The plates were then washed and anti-mouse Ig conjugated with horseradish peroxidase was added. After 30 minutes of incubation at room temperature, the plates were washed and developed. Cells from positive cells were transferred to 24-well plates and cloned by limiting dilution.

HMGBl stimulated TNF release The mouse macrophage cell line RAW 264.7 (available from the American Type Culture Collection (ATCC), Manassas, VA) was incubated with various concentrations of HMGBl for 4 hours at 37°C in serum-free Opti-MEM (Invitrogen, Carlsbad, CA). The supernatants were harvested and TNF level was measured using an ELISA kit (R&D Systems, Minneapolis, MN). The assay was also performed using heparinized whole blood, hi this case, HMGBl was diluted in Opti-MEM, added to 100 μl of whole blood to give a final volume of 200 μl, and placed in a U- bottom 96-well plate. The plates were then incubated for 4 hours at 37°C and plasma was harvested for ELISA analysis. To screen for blocking mAbs to HMGBl, purified mAbs were diluted in Opti-MEM and mixed with rat HMGBl at room temperature. After five minutes, the mixture was transferred into tissue culture wells containing RAW 264.7 cells. The plates were then incubated for 4 hours at 37°C and supernatants were harvested for ELISA analysis.

SDS-Poly acrylamide Gel Electrophoresis, Western Blot Analysis and Selectivity of HMGBl Monoclonal Antibodies For detection of HMGB 1 with the HMGB 1 mAbs, samples were mixed with

4X NuPAGE LDS Sample Buffer, 10X NuPAGE Sample Reducing Agent (Invitrogen, Carlsbad, CA). The samples were heated in boiling water for 5 minutes, immediately chilled on ice and loaded on an SDS-polyacrylamide gel. Western blot analysis was performed using standard techniques. For the experiments determining selectivity of the HMGB 1 monoclonal antibodies (i.e., selectivity for HMGBl and/or HMGB2), western blot analysis was performed on samples containing non-recombinant (i.e., natural) HMGBl from Chinese Hamster Ovary (CHO) cells (FIG. 11; labeled as CHO HMGBl; SEQ ID NO:36) or samples containing non-recombinant (i.e., natural) HMGB2 from Chinese Hamster Ovary (CHO) cells and some detectable recombinant human HMGB1-His₆ (FIG. 11; labeled as CHO HMGB2, rec-HMGB 1-His₅). FIGS. 18A and 18B depict the nucleotide and encoded amino acid sequences of the human recombinant HMGBl polypeptide containing a 5' 6 HIS tag (rec-HMGB 1-His₆; SEQ ID NOs:39 and 40). For the samples containing CHO HMGBl, samples contained -2.5-5 ng/μl of non-recombinant (i.e., natural) HMGBl from Chinese Hamster Ovary (CHO) cells. 20 μl of the sample (i.e., -50-100 ng of HMGBl) was loaded on a gel and subjected to SDS-PAGE. To isolate CHO HMGBl polypeptide, CHO cells were lysed and subsequently cleared by centrifugation. Anion exchange chromatography and heparin-affinity chromatography were then performed and fractions containing peak HMGBl immunoreactivity but no detectable HMGB2 immunoreactivity were pooled and used as the source of CHO HMGBl. For the samples containing non-recombinant (i.e., natural) HMGB2 from Chinese Hamster Ovary (CHO) cells and some detectable recombinant HMGB1-His₆ (FIG. 11; labeled as CHO HMGB2, rec-HMGB 1-His₆), CHO cells transfected with a recombinant HMGBl-His₆-expressing plasmid were utilized. To isolate CHO HMGB2 polypeptide, CHO cells were lysed and subsequently cleared by centrifugation. Anion exchange chromatography and heparin-affinity chromatography were then performed and fractions containing peak HMGB2 immunoreactivity, but no detectable natural HMGBl immunoreactivity, were pooled and used as the source of CHO HMGB2. In some cases, the pooled CHO HMGB2 fractions contained detectable amounts of recombinant HMGB-1-His₆ polypeptide, however, this recombinant HMGB-1-His₆ polypeptide was easily distinguished from HMGB2 based on its decreased mobility (and apparent higher molecular weight) when subjected to SDS-PAGE. Using the gel systems that generated the Western blots depicted in FIG. 11, non-recombinant CHO HMGB2 has an apparent molecular weight of -27,000, non-recombinant CHO HMGBl has an apparent molecular weight of -29,000 and recombinant HMGB-1-His₆ has an apparent molecular weight of -31,000. For the CHO HMGB2, rec-HMGB 1-His₆ samples, 20 μl of the sample (i.e., -10-20 ng of HMGB2) was loaded and subjected to SDS- PAGE. For the western blots depicted in FIG. 11, either an anti-His Tag antibody (Santa Cruz, CA; 2 μg/ml), an anti-HMGB2 antibody (Pharmingen, San Diego, CA; 2 μg/ml), an anti-HMGB 1/2 mAb (MBL International, Watertown, MA; 2 μg/ml) or particular anti-HMGBl monoclonal antibodies (e.g., 2E11 HMGBl mAb (CT3- 2E11), 1G3 HMGBl mAb (CT3-1G3), 6H9 HMGBl mAb (CT3-6H9), 2G7 HMGBl mAb (CT3-2G7), 2G5 HMGBl mAb (CT3-2G5) and 6E6 HMGBl mAb (CT3-6E6); 2 μg/ml for each) were used. Sequencing of Monoclonal Antibodies Total RNA was isolated from hybridoma cells using RNeasy MiniKit (Qiagen, Valencia, CA) as described in the kit protocol. The first strand of cDNA synthesis was performed using ProtoScript First Strand cDNA Synthesis kit (New England Biolabs, Catalog # E6500S) as designed in the kit protocol. 5 μl of cDNA was added to a PCR reaction (as described in the protocol for Mouse Ig-Primer Set, Catalog # 69831-3, Novagen, Madison, WI) containing 25 pmoles of the appropriate 5' primers (as described in the Novagen Ig-primer set protocol as MuIgGV_H5'-A, MuIgGV_H5'-B, MuIgGV_H5'-C, MuIgGV_H5'-D, MuIgGV_H5'-E, MuIgGV_H5'-F for heavy chain and MuIgGV_L5'-A, MuIgGV_L5'-B, MuIgGV_L5'-C, MuIgGV_L5'-D, MuIgGV_L5'-E, MuIgGV_L5'-F and MuIgGV_L5'-G for light chain) and 3' primers (as described in the Novagen Ig-primer set protocol as MuIgGV_H3'-2 for heavy chain and MuIgGV_L3'-2 for light chain). The PCR reaction conditions were 1 minute at 94°C, 1 minute at 50°C and 2 minutes at 72°C for 35 cycles, followed by an extension at 72°C for 6 minutes. PCR products were cloned into vector TOPO (hivitrogen, San Diego, CA). DNA sequence analysis was performed by Genaissance Pharmaceuticals (New Haven, CT).

HMGBl Peptide Binding Experiments Biotinylated peptides bound to React-Bind Streptavidin-Coated Plates (Pierce, Rockford, IL, Catalog # 15501) and non-biotinylated peptides bound to poly-D-lysine coated ELISA plates were used in anti-peptide ELISAs. Biotinylated peptides corresponding to particular 18 amino acid regions of human HMGBl, as well as a longer peptide corresponding to amino acid residues 9-85 of human HMGBl, were prepared and analyzed for binding to particular anti-HMGBl monoclonal antibodies by ELISA. These peptides, and their respective sequences, are depicted in FIG. 13 A. Poly-D-lysine coated plates were prepared by adding 60- 100 μl/well of 0.1 mg/ml solution of poly-D-lysine in water. Plates were then incubated at room temperature for 5 minutes and were rinsed with water to remove the solution. Briefly, using the molecular weight of the respective peptide, 1 mM peptide solutions were prepared in pyrogen-free water and diluted in IX phosphate buffered saline. Plate wells were washed three times with 200 μl of PBS and 100 μl of the various peptide solutions were added to designated wells. The plates were then covered and incubated for 60 minutes at room temperature. The wells were then washed three times with PBS, 0.05% polyoxyethylenesorbitan (referred to herein as Tween 20™) using a volume greater than 100 μl. 200 μl of blocking buffer (5% nonfat dry milk in PBS, 0.05% Tween 20™) was added to each of the wells. The plates were covered and incubated for 60 minutes at room temperature. The wells were then washed three times with PBS, 0.05% Tween 20™ using a volume greater than 100 μl. 100 μl of the primary antibody (e.g., 2E11 HMGBl mAb, 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb; 2 μg/ml in blocking buffer) was added to the designated wells and the plates were covered and incubated for 30 minutes at room temperature. The wells were then washed three times with PBS, 0.05% Tween 20™ using a volume greater than 100 μl. 100 μl of the goat anti-mouse horseradish peroxidase (HRP)-conjugated secondary antibody (Jackson ImmunoResearch Laboratories, West Grove, PA, Catalog No. 115-035-071; used at a 1:2000 dilution) was added to each of the wells. The plates were covered, incubated for 30 minutes at room temperature and subsequently washed three times with times with PBS, 0.05% Tween 20™ using a volume greater than 100 μl. The plates were developed by adding 50 μl of IX TMB (Sigma, St. Louis, MO) to each well, incubating for 10 minutes at room temperature and reading the absorbance at 655 nm using Microplate/Manager software and a BioRad Model 680 Plate Reader. Average background signal was subtracted from each of the sample signals.

Cecal Ligation and Puncture Cecal ligation and puncture (CLP) was performed as described previously (Fink and Heard, J. Surg. Res. 49:186-196 (1990); Wichmann et al, Crit. Care Med. 25:2078-2086 (1998); and Remick et al, Shock 4:89-95 (1995)). Briefly, BALB/c mice were anesthetized with 75 mg/kg ketamine (Fort Dodge, Fort Dodge, Iowa) and 20 mg/kg of xylazine (Bohringer higelheim, St. Joseph, MO) intramuscularly. A midline incision was performed, and the cecum was isolated. A 6-0 prolene suture ligature was placed at a level 5.0 mm from the cecal tip away from the ileocecal valve. The ligated cecal stump was then punctured once with a 22-gauge needle, without direct extrusion of stool. The cecum was then placed back into its normal infra-abdominal position. The abdomen was then closed with a running suture of 6- 0 prolene in two layers, peritoneum and fascia separately to prevent leakage of fluid. All animals were resuscitated with a normal saline solution administered sub- cutaneously at 20 ml/kg of body weight. Each mouse received a subcutaneous injection of imipenem (0.5 mg/mouse) (Primaxin, Merck & Co., Inc., West Point, PA) 30 minutes after the surgery. Animals were then allowed to recuperate. Mortality was recorded for up to 1 week after the procedure; survivors were followed for 2 weeks to ensure no late mortalities had occurred. Starting the day after the CLP procedure, 100 μg of particular anti-HMGBl monoclonal antibodies (i.e., 6E6 HMGBl mAb (mAB (6E6)); 2E11 HMGBl mAb (mAB (2E11)); 9G2 HMGBl mAb (mAB (9G2)) and a control IgG antibody were intraperitoneally administered to the mice once or twice a day for a total of 5 treatments. For the data presented in FIG. 16, various doses (1 μg/mouse, 10 μg/mouse or 100 μg/mouse) of 6E6 HMGBl mAb or a control IgG antibody were intraperitoneally administered.

HMGBl ELISA Two ELISA methods were performed using various HMGBl monoclonal antibodies.

HMGBl ELISA with Monoclonal (Capture) + Polyclonal (Detecto?) Antibody Pairs In the first method, ELISA plates were coated with a number of purified anti- HMGB 1 mAbs (e.g., 2E11 HMGBl mAb, 2G5 HMGBl mAb, 2G7 HMGB l mAb, 6E6 HMGBl mAb), and incubated overnight at 4°C. The plates were then blocked with PBS, 1 %BSA for one hour at 37°C. After washing, recombinant rat HMGBl was added at the indicated concentrations, and the plates were incubated at room temperature for 1 hour. The plates were then washed and incubated with rabbit polyclonal antibodies against HMGBl at 2 μg/ml (see U.S. Patent Nos. 6,303,321, 6,448,223 and 6,468,533). After 1 hour at room temperature, the plates were washed and incubated for 30 minutes with goat anti-rabbit Ig-HPR (Jackson JmmunoResearch Laboratories, West Grove, PA) diluted at 1:1000 in PBS. After washing, the plates were developed with TMB (Invitrogen, San Diego, CA) and absorbance at 655 nm was measured using a plate reader.

HMGBl ELISA with Monoclonal Antibody Pairs (Detection with 6E6 HMGBl mAb) ELISA plates were coated and blocked, and recombinant rat HMGBl was subsequently added as described above. After washing away the unbound HMGBl polypeptide, biotinylated 6E6 HMGBl mAb was added at 2 μg/ml and incubated for 1 hour at room temperature. Streptavidin-HRP was used to detect bound 6E6 HMGB 1 mAb and the plates were developed with TMB as described above.

Example 2: Identification and Characterization of Anti-HMGBl Monoclonal Antibodies A number of novel anti-HMGBl monoclonal antibodies have been isolated and purified from immunizations with either recombinant full-length rat HMGB1(SEQ ID NO:4; FIGS. 3A and 3B) or with a B-box polypeptide of human HMGBl (SEQ ID NO:3; FIG. 2B). A table summarizing characteristics (clone name, immunogen, isotype, purified antibody binding domain, and results of in vivo CLP assays) of these antibodies is depicted in FIG. 7.

Example 3: Determination of Selectivity of Anti-HMGBl Monoclonal Antibodies Experiments (e.g., ELISA, Western blot analysis) to determine the selectivity of the HMGBl monoclonal antibodies revealed that particular anti-HMGBl monoclonal antibodies are able to bind to the A box portion of HMGBl, the B box portion of HMGBl and/or the whole HMGBl protein. For example, as depicted in FIG.7, anti-HMGBl monoclonal antibodies were identified that can bind to the A box of HMGBl (e.g., 6E6 HMGBl mAb, 6H9 HMGBl mAb, 10D4 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2G5 HMGBl mAb, 4H11 HMGBl mAb, 7H3 HMGBl mAb, 9H3 HMGBl mAb). Other monoclonal antibodies were identified that bind to the B box of HMGBl (e.g., 2E11 HMGBl mAb, 3G8

HMGBl mAb, 3-5A6 HMGBl mAb, 9G1 HMGBl mAb, 4C9 HMGBl mAb, 1C3 HMGBl mAb, 5C12 HMGBl mAb, 3E10 HMGBl mAb, 7G8 HMGBl mAb, 4A10 HMGBl mAb).

Example 4: Determination of Nucleotide and Amino Acid Sequences of Anti- HMGBl Monoclonal Antibodies For particular HMGBl monoclonal antibodies (6E6 HMGBl mAb, 2E11 HMGBl mAb, 10D4 HMGBl mAb, 2G7 HMGBl mAb), nucleotide and encoded amino acid sequences of V_H domains and V_κ domains, including CDRs, were also obtained (FIGS. 4A-4D, 5A-5D, 6A-6D and 19A-19D).

Example 5: Inhibition of TNF Release by Anti-HMGBl Monoclonal Antibodies The ability of particular HMGBl monoclonal antibodies to inhibit TNF release was assessed. The results of this study are shown in FIGS. 8 and 9, which are histograms depicting TNF released by RAW 264.7 cells administered only HMGBl, HMGBl plus particular HMGBl monoclonal antibodies, or a control IgG antibody. FIG. 8 depicts the results of inhibition of HMGBl -mediated TNF release for 6E6 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb, 9G2 HMGBl mAb, and a control IgG antibody. FIG. 9 depicts the results of inhibition of HMGBl-mediated TNF release for 3G8 HMGBl mAb, 1 A9 HMGBl mAb, 9G2 HMGBl mAb, 6E6 HMGBl mAb, 2E11 HMGBl mAb, 10D4 HMGBl mAb, 6H9 HMGBl mAb, or a control IgG antibody. As depicted in FIGS. 8 and 9, particular HMGBl monoclonal antibodies (e.g., 6E6 HMGBl mAb, 10D4 HMGBl rnAb) inhibited TNF release, indicating that such antibodies could be used to modulate one or more HMGB functions (e.g., as described herein). For example, these blocking antibodies could be used to neutralize the biological activity of HMGBl (e.g., HMGBl -mediated activation of the cytokine cascade).

Example 6: Treatment of Septic Mice with Anti-HMGBl Monoclonal Antibodies Increases Survival of Mice Mice were subjected to cecal ligation and puncture (CLP), a well characterized model of sepsis caused by perforating a surgically-created cecal diverticulum, that leads to polymicrobial peritonitis and sepsis (Fink and Heard, supra; Wichmann et al, supra; and Remick et al, supra), and administered particular anti-HMGBl monoclonal antibodies (6E6 HMGBl mAb, 2E11 HMGBl mAb or 9G2 HMGBl) or a control IgG antibody (100 μg of antibody administered twice per day). Survival was monitored for 7 days. The results of this study are shown in FIG. 10, which is a graph of the survival of septic mice treated with either a control antibody or particular anti-HMGBl monoclonal antibodies. The results show that anti-HMGBl monoclonal antibodies administered to the mice starting 24 hours after the onset of cecal perforation rescued animals from death, as compared to administration of an IgG control antibody. For 6E6 HMGBl mAb, the rescue was significant at day 7 (p<0.03 versus control, Fisher's exact test). A dose response curve for survival of septic mice treated with 6E6 HMGBl mAb was also conducted. As depicted in FIG. 16, doses of 1, 10 and 100 μg of 6E6 HMGBl mAb were administered to mice. The results demonstrate that a dose of 10 μg of 6E6 HMGBl resulted in the greatest rescue of the septic mice.

Example 7: Selectivity of Anti-HMGBl Monoclonal Antibodies As described above, western blot analysis was performed using particular anti-HMGBl monoclonal antibodies. FIG. 11 depicts individual western blots of samples containing either CHO HMGB 1 or CHO HMGB2 and possibly recombinant HMGB1-His₆ (labeled as CHO HMGB2, rec-HMGB 1-His₆), which were probed with either an anti-His Tag antibody, an anti-HMGB2 antibody, an anti-HMGB 1/2 monoclonal antibody, or particular anti-HMGBl monoclonal antibodies (e.g., 2E11 HMGBl mAb, 1G3 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 2G5 HMGB1 mAb and 6E6 HMGBl mAb). The results of these experiments reveal that 2G7 HMGBl mAb binds HMGBl but does not detectably bind HMGB2, while 2E11 HMGBl mAb, 1G3 HMGBl mAb and 6H9 HMGBl mAb detect HMGB2 in addition to HMGBl.

Example 8: HMGBl Peptide Binding Experiments Biotinylated peptides corresponding to particular 18 amino acid regions of human HMGBl and a longer peptide corresponding to amino acid residues 9-85 of human HMGBl were prepared and analyzed for binding to particular anti-HMGBl monoclonal antibodies by ELISA. These peptides and their respective sequences are depicted in FIG. 13 A. The results of these peptide binding experiments are depicted in FIG. 13B. As depicted in FIG. 13B, 2E11 HMGBl mAb bound to a peptide corresponding to amino acid residues 151-168 of human HMGBl (i.e., amino acid residues 151-168 SEQ ID NO: 1). 6E6 HMGBl mAb and 6H9 bound to a peptide corresponding to amino acid residues 61-78 of human HMGBl (i.e., amino acid residues 61-78 SEQ ID NO: 1). 2G7 HMGBl mAb bound to a peptide corresponding to amino acid residues 46-63 of human HMGBl (i.e., amino acid residues 46-63 of SEQ LD NO:l). hi addition, 2G7 HMGBl mAb and 6E6 HMGBl mAb also bound the longer peptide corresponding to amino acid residues 9-85 of human HMGBl. These experiments demonstrate that particular anti-HMGBl monoclonal antibodies recognize different epitopes within the HMGBl polypeptide. For example, 6E6 HMGBl mAb, which was shown to inhibit HMGBl -mediated TNF release binds to an epitope contained within amino acids 61-78 of HMGBl. The discovery of a blocking epitope within this particular region of HMGBl could be used to screen for additional blocking agents (e.g., agents that inhibit an HMGBl function (e.g., HMGBl -mediated activation of the cytokine cascade)).

Example 9: HMGBl ELISA As depicted in FIGS. 14 and 15, two different ELISA methods were used to examine the properties of particular anti-HMGBl monoclonal antibodies. In one method, HMGBl monoclonal antibodies 2E11 HMGBl mAb, 2G5 HMGBl mAb, 2G7 HMGBl mAb, and 6E6 HMGBl mAb, were used as capture antibodies and a polyclonal HMGBl antibody was used as the detector antibody. In the other ELISA method, HMGBl monoclonal antibodies 2E11 HMGBl mAb, 2G5 HMGBl mAb, 2G7 HMGBl mAb, and 6E6 HMGBl mAb, were used as capture antibodies and 6E6 HMGBl mAb was used as the detector antibody. The results from both of the ELISA methods demonstrate that the monoclonal HMGBl antibodies can detect HMGBl and would be suitable for the diagnostic and/or prognostic methods described herein.

Example 10: Binding of 2G7 HMGBl mAb to HMGBl is Inhibited By a Peptide Corresponding to Amino Acid Residues 46-63 of HMGBl HMGBl peptide binding experiments using 2G7 HMGBl mAb were conducted. As described, biotinylated synthetic peptides corresponding to either amino acid residues 46-63 of human HMGBl or amino acid residues 61-78 of human HMGBl were prepared and analyzed for binding to 2G7 HMGBl mAb (2G7) by ELISA. Briefly, 2 μg/ml of 2G7 HMGBl mAb was added to plate wells containing either the HMGBl 46-63 peptide or the HMGBl 61-78 peptide at each of the indicated concentrations (0, 0.33, 1, 3, 9, 27, 81 and 243 μM peptide) for one hour at 25°C to prepare antibody-peptide samples. ELISA plates were coated with 10 μg/ml of recombinant rat HMGBl, and incubated overnight at 4°C. The plates were then blocked with reconstituted milk for one hour at 37°C. Antibody-peptide samples were then added at the concentrations listed above and incubated for one hour at room temperature. ^■ The plates were then washed and incubated with Streptavidin-HRP. After washing, the plates were developed with TMB (hivitrogen, San Diego, CA) and absorbance at 655 nm was measured using a plate reader. FIG. 20 depicts the results as percent of maximum signal (y-axis). As FIG. 20 demonstrates, the HMGBl 46-63 peptide inhibited the binding of 2G7 HMGBl mAb to bound HMGBl at all concentrations (depicted as a decrease in % of maximum signal). In contrast, the HMGBl 61-78 peptide did not inhibit the binding of 2G7 HMGB 1 mAb to HMGB 1. These experiments further confirm that 2G7 HMGB1 mAb binds to an epitope that is present in amino acids 46-63 of HMGBl.

Example 11 : Binding of 2E11 HMGBl mAb to HMGBl is Inhibited By Higher Concentrations of a Peptide Corresponding to Amino Acid Residues 151-168 of HMGBl HMGBl peptide binding experiments using 2E11 HMGBl mAb and biotinylated synthetic peptides conesponding to either amino acid residues 46-63 of human HMGBl (SEQ ID NO:23) or amino acid residues 151-168 of human HMGBl (SEQ ID NO: 30) were conducted as described herein The results of these experiments are depicted in FIG. 21 (as percent of maximum signal (y-axis)). As FIG. 21 demonstrates, the HMGBl 151-168 peptide significantly inhibited the binding of 2E11 HMGBl mAb to bound HMGBl at concentrations of 9 μM or greater. The HMGBl 151-168 peptide did not significantly inhibit the binding of 2E11 HMGBl mAb to HMGBl at concentrations of 3 μM or below (FIG. 21). In addition, the HMGBl 46-63 peptide did not inhibit the binding of 2E11 HMGBl mAb to HMGBl . These experiments confirm that 2E11 HMGBl mAb binds to an epitope that is present in amino acids 151-168 of HMGBl.

Example 12: 2G7 HMGBl mAb Recognizes an Epitope That is Present in Amino Acids 53-63 of HMGBl Various synthetic peptides were prepared. These synthetic peptides included a biotinylated peptide corresponding to amino acid residues 46-63 of human

HMGBl (SEQ ID NO:23; designated "huHMGBl -46-63 -B" or "Human HMGB1- 46-63-B"), a biotinylated peptide corresponding to amino acid residues 46-63 of human HMGB2 (SEQ ID NO:48; designated "huHMGB2-46-63-B" or "Human HMGB2-46-63-B"), a non-biotinylated peptide corresponding to amino acid residues 53-70 of human HMGBl (SEQ ID NO:47; designated "huHMGBl -53-70" or "Human HMGBl-53-70"), a biotinylated peptide corresponding to amino acid residues 61-78 of human HMGBl (SEQ ID NO:24; designated "huHMGBl -61-78- B"), a non-biotinylated peptide corresponding to amino acid residues 40-57 of human HMGBl (SEQ ID NO:46; designated "Human HMGB1-40-57") and a non- biotinylated peptide consisting of a scrambled amino acid sequence, wherein the amino acid residues that were scrambled were those of amino acid residues 46-63 of human HMGBl (SEQ ID NO:45; designated "Human HMGBl-46-63-scr"). By ELISA, as described herein, the binding of 2G7 HMGBl mAb to these overlapping peptides was analyzed to more specifically ascertain the epitope within HMGBl that binds to 2G7 HMGBl mAb. These peptides and their respective sequences are depicted in FIG. 23. The results of the peptide binding experiments are depicted in FIGS. 22 and 23. As shown in FIGS. 22 and 23, 2G7 HMGBl mAb bound to the HMGBl 46-63 peptide (i.e., amino acid residues 46-63 of SEQ ID NO:l or SEQ ID NO:23) but did not bind to the conesponding amino acid region of human HMGB2 (i.e., the HMGB2 46-63 peptide; amino acid residues 46-63 of SEQ ID NO:54 or SEQ JD NO:48). h addition, 2G7 HMGBl mAb bound to the HMGBl 53-70 peptide but did not bind the HMGBl 40-57 peptide. 2G7 HMGBl mAb also did not bind to the peptide consisting of a scrambled sequence of amino acid residues 46-63 of

HMGBl. In addition to showing the binding of 2G7 HMGBl mAb to the various synthetic peptides, FIG. 22 also depicts the binding of avidin to these synthetic peptides. In Example 8, it was shown that 2G7 HMGBl mAb binds to an epitope contained within amino acid residues 46-63 of HMGB 1. Given that 2G7 HMGB 1 mAb binds the HMGBl 46-63 peptide and the HMGBl 53-70 peptide, these experiments demonstrate that 2G7 HMGBl mAb recognizes an epitope present in the amino acid region consisting of amino acid residues 53-63 of HMGBl. These experiments further demonstrate that 2G7 HMGBl mAb does not bind to the HMGB2 46-63 peptide, notwithstanding only a single amino acid difference between the HMGBl 46-63 peptide and the HMGB2 46-63 peptide. As such, the glycine residue at position 58 of HMGBl (Gly-58), which is a corresponding serine residue in HMGB2, is an important amino acid residue in the HMGBl epitope recognized by 2G7 HMGBl mAb (FIG. 23). Example 13: 6E6 HMGBl mAb Recognizes an Epitope That is Present in Amino Acids 67-78 of HMGBl Various synthetic peptides were prepared. These synthetic peptides included a non-biotinylated peptide corresponding to amino acid residues 53-70 of human HMGBl (SEQ ID NO:47; designated "Human HMGB1-53-70-B"; described above), a non-biotinylated peptide corresponding to amino acid residues 67-84 of human HMGBl (SEQ ID NO:50; designated "Human HMGB 1-67-84"), a biotinylated peptide corresponding to amino acid residues 61-78 of human HMGBl (SEQ JJD NO:24 designated "Human HMGB1-61-78-B") and a non-biotinylated peptide consisting of a scrambled amino acid sequence, wherein the amino acid residues that were scrambled were those of amino acid residues 61-78 of human HMGBl (SEQ TD NO:49; designated "Human HMGBl-61-78_scr"). By ELISA, as described herein, the binding of 6E6 HMGBl mAb to these overlapping peptides was analyzed to more specifically ascertain the epitope within HMGBl that binds to 6E6 HMGBl mAb. These peptides, their respective sequences and which of the peptides were bound by 6E6 HMGB 1 mAb are depicted in FIG. 24. The results of these peptide binding experiments are depicted in FIG. 24. As shown in FIG. 24, 6E6 HMGBl mAb bound to the HMGBl 61-78 peptide (SEQ ID NO:24). Further, 6E6 HMGBl mAb bound to the HMGBl 67-84 peptide (SEQ ID NO:50) but did not bind to the HMGBl 53-70 peptide (SEQ ID NO:47) (FIG. 24). 6E6 HMGBl mAb also did not bind to the peptide consisting of a scrambled sequence of amino acid residues 61-78 of HMGBl (SEQ ID NO:49) (FIG. 24). In Example 8, it was shown that 6E6 HMGBl mAb binds to an epitope contained within amino acid residues 61-78 of HMGBl. Given that 6E6 HMGBl mAb binds to the HMGBl 61-78 peptide and the HMGBl 67-84 peptide, these experiments demonstrate that 6E6 HMGBl mAb recognizes an epitope present in the amino acid region consisting of amino acid residues 67-78 of HMGBl.

Example 14: HMGBl Peptide Binding Experiments with 2E11 HMGBl mAb Various synthetic peptides were prepared. These synthetic peptides included a biotinylated peptide corresponding to amino acid residues 151-168 of human HMGB1 (SEQ ID NO:30; designated "Human HMGB1-151-168-B"), a non- biotinylated peptide corresponding to amino acid residues 143-160 of human HMGBl (SEQ JX> NO:52; designated "Human HMGB1-143-160"), a non- biotinylated peptide corresponding to amino acid residues 157-174 of human HMGBl (SEQ ID NO:53; designated "Human HMGBl-157-174"), and a non- biotinylated peptide corresponding to a scrambled amino acid sequence, wherein the amino acid residues that were scrambled were those of amino acid residues 151-168 of human HMGBl (SEQ ID NO:51; designated "Human HMGBl-151-168_scr"). By ELISA, as described herein, the binding of 2E11 HMGBl mAb to these overlapping peptides was analyzed to more specifically ascertain the epitope within HMGBl that binds to 2E11 HMGBl mAb. These peptides, their respective sequences and which of the peptides were bound by 2E11 HMGBl mAb are depicted in FIG. 25. As depicted in FIG. 25, 2E11 HMGBl mAb bound to the HMGBl 151-168 peptide (SEQ ID NO:30), but did not bind to either the HMGB 1 143-160 peptide (SEQ ID NO:52) or the HMGBl 157-174 peptide (SEQ ID NO:53). As is known in the art, there are two types of epitopes or antigenic determinants: linear, sequential or continuous epitopes and non-linear, conformational or discontinuous epitopes. The dimensions of a typical antibody epitope are often given as 6 amino acid residues in size, but can be of variable size. These experiments suggest that the epitope recognized by 2E11 HMGBl mAb is likely to comprise amino acid residues 156-161 of HMGBl. However, 2E11 HMGBl mAb may also recognize an epitope that includes flanking amino acids to this region, e.g., amino acid residues 155-161, 155-162, 156-162 and/or 156-163 of HMGBl. A summary of the peptide binding results depicting the mapped epitopes of

HMGBl that are recognized by various HMGBl mAbs (e.g., 2G7 HMGBl mAb, 6E6 HMGBl mAb, 2G5 HMGBl mAb, 6H9 HMGBl mAb, 2E11 HMGBl mAb) is shown in FIG. 26.

Example 15: Mass Spectrometry of 6E6 HMGBl mAb The mass of 6E6 HMGBl mAb was determined by mass spectrometry. 6E6 HMGBl mAb was sent to Novatia, LLC (Princeton, NJ) for LC/MS analysis. Briefly, the antibody, either intact or after being treated with DTT (to separate heavy and light chains), was subjected to analysis using a PLRP-s 4000A reverse phase HPLC column (HPLC/ESI-MS system) and mass spectroscopy (Finnigan TSQ7000 mass spectrometer). Mass accuracy for proteins is generally ± 0.01%, and this accuracy was achieved in measuring the mass of the 6E6 light chain (e.g., 2 Da/23,917 Da x 100% = 0.008%). The results of this analysis are shown in FIGS. 27A-27D, which depicts a mass spectrum plot. The total mass of 6E6 HMGB 1 mAb was 146.5 kDa (FIG. 27 A; depicting mass spectrum for intact 6E6 HMGBl mAb). The masses of the light and heavy chains of 6E6 HMGBl mAb were determined to be 23.9 kDa (FIGS. 27B and 27C) and 49.4 kDa (FIGS. 27B and 27D), respectively. The predicted masses for the light and heavy chains, as calculated using amino acid molecular weights, are 23.9 kDa and 47.9 kDa, respectively.

Example 16: 2G7 HMGBl mAb Increases Survival in Septic Mice After Administration of a Single Dose Mice were subjected to cecal ligation and puncture (CLP) as described above, hi one experiment, twenty-four hours after surgery, mice were intraperitoneally administered either 0.004 mg/kg, 0.04 mg/kg or 0.4 mg/kg of 2G7 HMGBl mAb (2G7) once per day. In a second experiment, twenty-four hours after surgery, mice were administered either 0.04 mg/kg of 2G7 HMGBl mAb or 0.4 mg/kg of control IgG (IgG control) once per day. Survival was monitored for 14 days for both experiments. The results of the two experiments are combined and presented in FIG. 28. Administration of 0.4 mg/kg of 2G7 HMGB 1 mAb resulted in approximately 85% survival at 14 days after CLP, as compared to approximately only 40%) survival of mice administered with IgG control at 14 days after CLP (FIG. 28). Further, as depicted in FIG.28, administration of 0.04 mg/kg and 0.004 mg/kg of 2G7 HMGBl mAb resulted in approximately 60% and 50% survival at 14 days after CLP, respectively. FIG. 29 is a table comparing CLP survival percentages in mice administered various doses (either 4 mg/kg, 0.4 mg/kg, 0.04 mg/kg or 0.004 mg/kg) of 6E6 HMGBl mAb, 2G7 HMGBl mAb or control IgG. As depicted in FIG. 29, the mice were administered the antibodies 4 times a day intraperitoneally. The results demonstrate that administration of a dose of 0.4 mg/kg of either 6E6 HMGBl mAb or 2G7 HMGBl mAb resulted in greater than 80% of the septic mice surviving to 14 days post-CLP, as compared to only approximately 40% of the septic mice surviving to 14 days post-CLP when administered control IgG.

Example 17: Inhibition of TNF Release by Anti-HMGBl Monoclonal Antibodies As in Example 5, the ability of particular HMGBl monoclonal antibodies to inhibit TNF release was assessed. The results of this study are shown in FIGS. 32 and 33, which are histograms depicting TNF released by RAW 264.7 cells administered only HMGBl (dark bar), or HMGBl plus particular HMGBl monoclonal antibodies. FIG. 32 depicts the results of inhibition of HMGBl - mediated TNF release for 1 A9 HMGBl mAb (1A9); 2E11 HMGBl mAb (2E11); 2G5 HMGBl mAb (2G5); 2G7 HMGBl mAb (2G7); 3G8 HMGBl mAb (3G8); 4H11 HMGBl mAb (4H11); 5A6 HMGBl mAb (5A6); 6E6 HMGBl mAb (6E6); 9G2 HMGBl mAb (9G2); 4C9 HMGBl mAb (4C9); and 6H9 HMGBl mAb (6H9). FIG. 33 depicts the results of inhibition of HMGBl -mediated TNF release for 7H3 HMGBl mAb (7H3); 9H3 HMGBl mAb (9H3); 10D4 HMGBl mAb (10D4); 1C3 HMGBl mAb (1C3); 3E10 HMGBl mAb (3E10); 4A10 HMGBl mAb (4A10); 5C12 HMGBl mAb (5C12); and 7G8 HMGBl mAb (7G8). As depicted in FIGS. 32 and 33, and further to the results described in Example 5, particular HMGBl monoclonal antibodies (e.g., 2E11 HMGBl mAb, 4H11 HMGBl mAb, 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb) inhibited TNF release, indicating that such antibodies could be used to modulate one or more HMGB functions (e.g., as described herein). For example, these blocking antibodies could be used to neutralize the biological activity of HMGBl (e.g., HMGBl -mediated activation of the cytokine cascade). While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

CLAJMSWhat is claimed is:

1. An antibody or antigen-binding fragment thereof that specifically binds to a vertebrate high mobility group box (HMGB) A box but does not specifically bind to non-A box epitopes of HMGB, wherein said antibody or antigen- binding fragment inhibits release of a proinflammatory cytokine from a vertebrate cell treated with a high mobility group protein.

2. The antibody or antigen-binding fragment of Claim 1 wherein said vertebrate high mobility group box (HMGB) A box is a mammalian HMGB A box.

3. The antibody or antigen-binding fragment of Claim 2 wherein said mammalian high mobility group box (HMGB) A box is a human HMGB A box.

4. The antibody or antigen-binding fragment of Claim 2 wherein said mammalian high mobility group box (HMGB) A box is an HMGB T A box.

5. The antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment is an antigen-binding fragment selected from the group consisting of a Fab fragment, a Fab' fragment, a F(ab')₂ fragment and a Fv fragment.

6. The antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment is a monoclonal antibody or an antigen-binding fragment thereof.

7. The monoclonal antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment is selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb.

8. The antibody or antigen-binding fragment of Claim 4 wherein the binding of said antibody or said antigen-binding fragment to said high mobility group box (HMGB) A box can be inhibited by an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb.

9. The antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment has the epitopic specificity of 6E6 HMGBl mAb, 6H9 HMGBl mAb and/or 10D4 HMGBl mAb.

10. The antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment has the epitopic specificity of 6H9 HMGBl mAb.

11. The antibody produced by murine hybridoma 6E6 HMGB 1 mAb, deposited as ATCC Accession Number PTA-5433, or an antigen-binding fragment thereof.

12. The antibody produced by murine hybridoma 6H9 HMGBl mAb, deposited as ATCC Accession Number PTA-5434, or an antigen-binding fragment thereof.

13. The antibody produced by murine hybridoma 10D4 HMGB 1 mAb, deposited as ATCC Accession Number PTA-5435, or an antigen-binding fragment thereof.

14. Murine hybridoma 6E6 HMGBl mAb, deposited as ATCC Accession Number PTA-5433.

15. Murine hybridoma 6H9 HMGB 1 mAb, deposited as ATCC Accession Number PTA-5434.

16. Murine hybridoma 10D4 HMGB 1 mAb, deposited as ATCC Accession Number PTA-5435.

17. The antibody or antigen-binding fragment of Claim 4 wherein said antibody or antigen-binding fragment is selected from the group consisting of a human antibody, a humanized antibody, a chimeric antibody and an antigen-binding fragment of any of the foregoing.

18. An isolated cell that produces an antibody or antigen-binding fragment thereof that specifically binds to a vertebrate high mobility group box (HMGB) A box but does not specifically bind to non-A box epitopes of HMGB.

19. The isolated cell of Claim 18 wherein said vertebrate high mobility group box (HMGB) A box is a mammalian HMGB A box.

20. The isolated cell of Claim 19 wherein said mammalian high mobility group box (HMGB) A box is a human HMGB A box.

21 The isolated cell of Claim 19 wherein said mammalian high mobility group box (HMGB) A box is a mammalian HMGBl A box.

22. The isolated cell of Claim 18 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-bmding fragment thereof.

23. The isolated cell of Claim 18 wherein said antibody or antigen-bmding fragment is a monoclonal antibody or an antigen-binding fragment thereof.

24. The isolated cell of Claim 18 wherein said antibody or antigen-binding fragment is selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb.

25. The isolated cell of Claim 18 that produces an antibody or antigen-binding fragment thereof, wherein the binding of said antibody or said antigen- binding fragment to said high mobility group box (HMGB) A box can be inhibited by an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb.

26. The isolated cell of Claim 18 that produces an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment has the epitopic specificity of an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb and 10D4 HMGBl mAb.

27. The antibody produced by murine hybridoma 2E11 HMGBl mAb, deposited as ATCC Accession Number PTA-5431, or an antigen-binding fragment thereof.

28. An antibody or antigen-binding fragment thereof, wherein the binding of said antibody or said antigen-binding fragment to a vertebrate high mobility group box (HMGB), polypeptide can be inhibited by 2E11 HMGBl mAb.

29. An antibody or antigen-bindmg fragment thereof, wherein said antibody or antigen-binding fragment has the epitopic specificity of 2E11 HMGBl mAb.

30. Murine hybridoma 2E11 HMGBl mAb, deposited as ATCC Accession Number PTA-5431.

31. An isolated cell that produces 2E11 HMGB 1 mAb.

32. The isolated cell of Claim 31 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

33. An isolated cell that produces an antibody or antigen-binding fragment thereof, wherein the binding of said antibody or said antigen-binding fragment to a vertebrate high mobility group box (HMGB) polypeptide can be inhibited by 2E11 HMGBl mAb.

34. The isolated cell of Claim 33 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

35. An isolated cell that produces an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment has the epitopic specificity of 2E11 HMGBl mAb.

36. The isolated cell of Claim 35 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

37. The antibody produced by murine hybridoma 2G7 HMGB 1 mAb, deposited as ATCC Accession Number PTA-5432, or an antigen-binding fragment thereof.

38. An antibody or antigen-binding fragment thereof, wherein the binding of said antibody or said antigen-binding fragment to a vertebrate high mobility group box (HMGB) polypeptide can be inhibited by 2G7 HMGBl mAb.

39. An antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment has the epitopic specificity of 2G7 HMGBl mAb.

40. Murine hybridoma 2G7 HMGBl mAb, deposited as ATCC Accession Number PTA-5432.

41. An isolated cell that produces 2G7 HMGBl mAb.

42. The isolated cell of Claim 41 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

43. An isolated cell that produces an antibody or antigen-binding fragment thereof, wherein the binding of said antibody or said antigen-binding fragment to a vertebrate high mobility group box (HMGB) polypeptide can be inhibited by 2G7 HMGB 1 mAb.

44. The isolated cell of Claim 43 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

45. An isolated cell that produces an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment has the epitopic specificity of 2G7 HMGBl mAb.

46. The isolated cell of Claim 45 wherein said isolated cell is selected from the group consisting of an immortalized B cell, a hybridoma and a recombinant cell comprising one or more exogenous nucleic acid molecules that encode said antibody or antigen-binding fragment thereof.

47. An antibody or antigen-binding fragment that binds to a peptide consisting of amino acid residues 151 to 168 of SEQ ID NO: 1.

48. The antibody or antigen-binding fragment of Claim 47 wherein said antibody or antigen-binding fragment is a monoclonal antibody or an antigen-binding fragment thereof.

49. An antibody or antigen-binding fragment that binds to a peptide consisting of amino acid residues 156 to 161 of SEQ LD NO: 1.

50. An antibody or antigen-binding fragment that binds to a peptide selected from the group consisting of: a peptide consisting of amino acid residues 155 to 161 of SEQ ID NO:l; a peptide consisting of amino acid residues 155 to 162 of SEQ ID

NO:l; a peptide consisting of amino acid residues 156 to 162 of SEQ JD NO:l; and a peptide consisting of amino acid residues 156 to 163 of SEQ ID NO:l.

51. An antibody or antigen-binding fragment, wherein the binding of said antibody or said antigen-binding fragment to a peptide consisting of amino acid residues 151 to 168 of SEQ JD NO:l can be inhibited by 2E 11 HMGBl mAb.

52. An antibody or antigen-binding fragment that binds to a peptide consisting of amino acid residues 61 to 78 of SEQ ID NO:l.

53. The antibody or antigen-binding fragment of Claim 52 wherein said antibody or antigen-binding fragment is a monoclonal antibody or an antigen-binding fragment thereof.

54. An antibody or antigen-binding fragment that binds to a peptide consisting of amino acid residues 67 to 78 of SEQ ID NO:l.

55. An antibody or antigen-binding fragment, wherein the binding of said antibody or said antigen-binding fragment to a peptide consisting of amino acid residues 61 to 78 of SEQ JO NO:l can be inhibited by an antibody selected from the group consisting of 6E6 HMGB 1 mAb and 6H9 HMGB 1 mAb.

56. An antibody or antigen-binding fragment, wherein the binding of said antibody or said antigen-binding fragment to a peptide consisting of amino acid residues 67 to 78 of SEQ ID NO:l can be inhibited by 6E6 HMGBl mAb.

57. An antibody or antigen-bindmg fragment that binds to a peptide consisting of amino acid residues 46 to 63 of SEQ ID NO:l.

58. The antibody or antigen-binding fragment of Claim 57, wherein said antibody does not bind to a peptide consisting of amino acid residues 46 to 63 of SEQ ID NO:54.

59. The antibody or antigen-binding fragment of Claim 57 wherein said antibody or antigen-binding fragment is a monoclonal antibody or an antigen-binding fragment thereof.

60. An antibody or antigen-binding fragment, wherein the binding of said- antibody or said antigen-binding fragment to a peptide consisting of amino acid residues 46 to 63 of SEQ JD NO:l can be inhibited by 2G7 HMGBl mAb.

61. An antibody or antigen-binding fragment thereof wherein said antibody or fragment comprises the light chain CDRs (CDR1, CDR2 and CDR3) and the heavy chain CDRs (CDR1, CDR2 and CDR3) of an antibody selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and 2G7 HMGBl mAb.

62. The antibody or antigen-binding fragment of Claim 61 wherein said antibody or antigen-binding fragment further comprises a human framework region.

63. The antibody or antigen-binding fragment of Claim 1 wherein said antibody or antigen-binding fragment is an antigen-binding fragment selected from the group consisting of a Fab fragment, a Fab' fragment, a F(ab')₂ fragment and a Fv fragment.

64. A composition comprising the antibody or antigen-binding fragment of Claim 1 and a pharmaceutically-acceptable excipient.

65. A composition comprising an antibody or antigen-binding fragment thereof and a pharmaceutically-acceptable excipient, wherein said antibody or antigen-binding fragment is selected from the group consisting of 6E6 HMGBl mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb and an antigen-binding fragment of any of the foregoing.

66. The antibody or antigen-binding fragment of Claim 1 wherein said antibody or antigen-binding fragment is selected from the group consisting of a human antibody, a humanized antibody, a chimeric antibody and an antigen-binding fragment of any of the foregoing.

67. An antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-binding fragment of a), b), c), d), e) , f) or g).

68. The antibody or antigen-binding fragment of Claim 67 wherein said antibody or antigen-binding fragment is selected from the group consisting of a human antibody, a humanized antibody, a chimeric antibody and an antigen-binding fragment of any of the foregoing.

69. A method of detecting and/or identifying an agent that binds to a vertebrate high mobility group box (HMGB) polypeptide comprising combining: i) an antibody or antigen-binding fragment that binds HMGB; ii) a test agent; and iii) a composition comprising a vertebrate HMGB polypeptide; and detecting or measuring the formation of a complex between said antibody or antigen-binding fragment and said HMGB polypeptide, wherein a decrease in the formation of said complex relative to a suitable control indicates that said test agent binds to said HMGB polypeptide, wherein said antibody or antigen-binding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 . mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-binding fragment of a), b), c), d), e) , f) or g).

70. A method of treating a condition in a subject characterized by activation of an inflammatory cytokine cascade comprising administering to the subject an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-binding fragment of a), b), c), d), e) , f) or g).

71. The method of Claim 70 wherein said condition is selected from the group consisting of sepsis, allograft rejection, arthritis, asthma, lupus, adult respiratory distress syndrome, chronic obstructive pulmonary disease, psoriasis, pancreatitis, peritonitis, bums, ischemia, Behcet's disease, graft versus host disease, inflammatory bowel disease, multiple sclerosis, and cachexia.

72. A method of treating a subject with sepsis comprising administering to the subject an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-bindmg fragment of a), b), c), d), e) , f) or g).

73. A method of treating a subject with arthritis comprising admimstering to the subject an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-binding fragment of a), b), c), d), e) , f) or g).

A method of treating a subject with lupus comprising administering to the subject an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-bmding fragment is selected from the group consisting of: a) 6E6 HMGBl mAb; b) 6H9 HMGBl mAb; c) 2G7 HMGBl mAb; d) 10D4 HMGBl mAb; e) 2E11 HMGBl mAb; f) an antibody having the epitopic specificity of 6E6 HMGB 1 mAb, 6H9 HMGBl mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb and/or 2E11 HMGBl mAb; g) an antibody that can compete with 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGB 1 mAb, 10D4 HMGB 1 mAb and/or 2E11 HMGB 1 mAb for binding to a vertebrate high mobility group box (HMGB) polypeptide; and h) an antigen-binding fragment of a), b), c), d), e) , f) or g).

75. A method of detecting a vertebrate high mobility group box (HMGB) polypeptide in a sample comprising: a) contacting a sample with an antibody or antigen-binding fragment of Claim 62, under conditions suitable for binding of said antibody or fragment to said HMGB polypeptide present in said sample; and b) detecting antibody-HMGB complexes or antigen-binding fragment- HMGB complexes, wherein detection of said antibody-HMGB complexes or antigen- binding fragment-HMGB complexes is indicative of the presence of HMGB polypeptide in said sample.

76. The method of Claim 75 wherein said antibody or antigen-binding fragment is selected from the group consisting of 6E6 HMGB 1 mAb, 6H9 HMGB 1 mAb, 2G7 HMGBl mAb, 10D4 HMGBl mAb, 2E11 HMGBl mAb and an antigen-binding fragment of any of the foregoing.

77. The method of Claim 75, wherein said antibody or antigen-binding fragment comprises a detectable label.

78. The method of Claim 75 wherein said detecting of antibody-HMGB complexes or antigen-binding fragment-HMGB complexes is by immunoassay.

79. The method of Claim 78 wherein said immunoassay is an ELISA.

80. A test kit for use in detecting the presence of a vertebrate high mobility group box (HMGB) polypeptide or portion thereof in a sample comprising: a) an antibody or antigen-binding fragment of Claim 62; and b) one or more ancillary reagents suitable for detecting the presence of a complex between said antibody or antigen-bmding fragment and said HMGB polypeptide or portion thereof.