Islet cell antibodies represent autoimmune response against several antigens.
To study the antigens involved in the islet cell antibody (ICA) reaction we selected 30 patient serum samples (ten in each group) positive for ICA and one other additional autoantibody, such as glutamic acid decarboxylase antibodies (GADA), thyrosine phosphatase antibodies (IA-2A) or insulin autoantibodies (IAA). The serum samples were incubated with the specific antigen (GAD65, IA-2 or insulin) and the ICA analysis and the corresponding immunoprecipitation assay were performed before and after the absorption. We could then demonstrate that specific autoantibodies against GAD65 and IA-2 could be absorbed with the corresponding antigen, since ten GADA positive and six IA-2A samples turned completely negative. However, the ICA reaction after absorption with GADA, IA-2A and insulin was still present, although at significantly lower levels. The results strongly indicate that the ICA reaction represents simultaneous autoimmunity against several other antigens beside GAD65, IA-2 and insulin.
D000293:Adolescent; D000328:Adult; D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology*; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology*; D007527:Isoenzymes / Q000276:immunology; D008565:Membrane Proteins / Q000276:immunology; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000276:immunology; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8
D001323:Autoantibodies; D001324:Autoantigens; D007527:Isoenzymes; D008565:Membrane Proteins; C024211:islet cell antibody; C516862:PTPRN protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2