Conserved Epitopes in the Protein Tyrosine Phosphatase Family of Diabetes Autoantigens

Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, Colorado, USA.
Annals of the New York Academy of Sciences (Impact Factor: 4.38). 01/2009; 1150(1):245-7. DOI: 10.1196/annals.1447.035
Source: PubMed


IA2 and phogrin are important targets of humoral and cell-mediated autoimmunity in type 1 diabetes in man. They belong to a conserved subfamily of transmembrane protein tyrosine phosphatases (PTPs) associated with the regulatory pathway of secretion. To examine potential cross-reactivity between PTP family members we tested sera from T1D patients for reactivity to IA2, and the Drosophila (FLYDA) and C. elegans (IDA) orthologs using radioimmunoprecipitation assays of (35)S Met-labeled in vitro translated products of the cytosolic domains of these proteins. Approximately 80% of sera reacted with at least one probe. Of these, 82.5% showed reactivity to human IA2, 74.1% to FLYDA, and 33.7% to IDA. The majority of sera that bound FLYDA and/or IDA also recognized IA2. This raises the possibility that in some cases reactivity to IA2 may have arisen by molecular mimicry.

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