IA-2, a transmembrane protein of the protein tyrosine phosphatase family, is a major autoantigen in insulin-dependent diabetes mellitus

摘要: IA-2 is a 105,847 Da transmembrane protein that belongs to the tyrosine phosphatase family. Immunoperoxidase staining with antibody raised against showed this expressed in human pancreatic islet cells. In study, we full-length cDNA clone of rabbit reticulocyte transcription/translation system and used recombinant radiolabeled detect autoantibodies by immunoprecipitation. Coded sera (100) were tested: 50 from patients newly diagnosed insulin-dependent diabetes mellitus (IDDM) age-matched normal controls. Sixty-six percent patients, but none controls, reacted IA-2. The same diabetic tested for cells (ICA) indirect immunofluorescence glutamic acid decarboxylase (GAD65Ab) depletion ELISA 68% 52% positivity, respectively. Up 86% IDDM had and/or GAD65. Moreover, greater than 90% (14 15) ICA-positive GAD65Ab-negative Absorption experiments reactivity was greatly reduced prior incubation or GAD65 when respective present. A little over one-half (9 16) negative ICA found be positive GAD65, arguing test less sensitive tests It concluded major cell autoantigen IDDM, and, together responsible much islets. Tests detection may eventually replace population screening.