The invention relates to a carrier for the detection and determination of an immunological reaction partner present in a liquid, the associated partner being on the surface of the c,^arrier.
It is known to bind a partner of an immunolo~ical reaction adsorptively or covalently to a carrier in order to isolate the corresponding partner from a solution in or-der to detect this partner or to determine its amount.
However, it is al50 known that test methods based On this principle can have deficiencies.
Thus, Chessum and Denmark describe, in The Lancet (1978), page 161, that the known polystyrene microtiter plates used as the carrier in a process for the deter-mination of antigens or antibodies which is generally called ELISA (Enzyme Linked Immuno Sorbent Assay) can lead to intolerably large variations in the test result.
Bidwell et al. also report, in J. Infect. Disease 136, Supplement, page 27~ (1977), variations in the results of an ELISA test which it was possible to attribute to differences in the microtiter plates used as the carrier.
These wide varia-tions in the test result which were caused by differences in the surface properties of the microtiter plates should not be restricted to the use of these plates, but should also occur with carriers of a different shape made from the same materials.
Accordingly, there was the object of discovering '7'7~
carrier materials which have more uniform surface pro-perties and which, when used, give immunological test results which vary less.
Surprisingly, it has now been Eound that this object can be achieved by irradiating the carrier material, and preferably microtiter plates prepared therefrom, with gamma rays, preferably with cobalt rays, and preferably with 0.1 to 100, in particlular 0.5 to 10, megarads.
The invention thus relates to a process for preparing a polymeric carrier for the detection and determination o~ a partner o an immunological reaction in which the corresponding partner is on the surface of the carrier, wherein the carrier is irradiated, before or after its surface has been coated with this partner.
It is not necessary to coat the carrier immediately after irradiation. The advantageous effect of irradiation is also observed if a period of days or months elapses between irradiation and coating.
In principle, all plastics, but in particular polystyrene and polyvinyl chlcride~ can be used as carrier materials in this process.
Irradiated carriers can advantageously be used in immune test systems which are known per se, for example immune test systems based on an antigen/antibody reaction, for example ELISA systems (Enzyme Linked Immuno Sorbent Assay systems), a bonding partner being bonded to the irradiated 77~
Such bonding partners can be, for example, proteins, such as immunoglobulins, antimicrobial anti-bodies, plasma proteins, for example Clq, or antigenic materials, for example allergens or microbial antigens.
The example whi.ch follows illustrates the invention:
Preparation of a test kit for the determination of anti-bodies of the IgG class and IgM class against mumps virus in human serum.
1. Bonding of the virus antigen to the carrier (polystyrene microtiter plate) a. irradiated (about 2 mrad~
b. not irradiated 15 2. Washing 3. Application and incubation of serum dilutions 4. Washing 5. Application and incubation of anti-human IgG- or IgM-alkaline phosphatase conjugate 20 6. Washing 7. Application of the substrate solution 8. Stopping of enzymatic splitting by addition of 2N NaOH
9. Photometric measurement at 405 nm ~7~
Table Comparison of the sensitivity of a test with an irradi-ated carrier with that of a test with a non-irradiated carrier:
Detection limit (titer 1:) irradiated carrier non-irradiated carrier Serum IgG IgM ~ IgG I~M
A 20,480 20,480 1,280 2,560 10 3 1,280 160 640 The figures show the advantage of using irradi-ated carriers. The detectability (sensitivity) is significantly increased.