Demonstration of anti-keratin antibodies by ELISA using keratin or thiol-containing compounds in urea as antigens.
During the development of an enzyme-linked immunosorbent assay (ELISA) for the demonstration of anti-keratin antibodies (AKA) it was observed that rabbit anti-keratin antisera also reacted with polystyrene surfaces treated with beta-mercaptoethanol in 8 M urea (ME-urea). Sera from non-immunized rabbits or rabbits immunized with antigens unrelated to keratin failed to react. The specificity of the reaction was further assessed by absorption experiments and by testing affinity-purified AKA. IgM activity against ME-urea could be demonstrated in 62.5% of sera from patients with infectious mononucleosis and in 37.5% of sera from patients with rheumatoid arthritis, and there was a good correlation to the presence of AKA. Coating of the solid phase with compounds containing free SH groups in 4-8 M urea generated the antigen of this ELISA. The exact molecular configuration of this presumptive synthetic antigen is obscure, but the ME-urea ELISA seems to provide a simple way to detect anti-keratin antibodies of a certain specificity.
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D000937:Antigen-Antibody Reactions; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007633:Keratins / Q000276:immunology*; D008623:Mercaptoethanol / Q000276:immunology; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000276:immunology*; D014508:Urea / Q000276:immunology*
D000906:Antibodies; D007106:Immune Sera; D007075:Immunoglobulin M; D013438:Sulfhydryl Compounds; D008623:Mercaptoethanol; D007633:Keratins; D014508:Urea