IDENTIFICATION OF AUTOIMMUNE THROMBOCYTOPENIC PURPURA-RELATED EPITOPES USING PHAGE-DISPLAY PEPTIDE LIBRARY

A random heptapeptide phage-displayed library was screened with two se rum samples from autoimmune thrombocytopenic purpura (AITP) patients t o address the repertoire of autoantigenic epitopes involved in platele t destruction. We obtained a panel of affinity-selected phage clones t hat have been shown to react in enzyme-linked immunosorbent assay with autoantibodies from other AITP patients. None of the peptides obtaine d has been described previously as possibly being an epitope for antip latelet antibodies, and the majority of them did not show any homology with known platelet glycoproteins. We conclude that peptides identifi ed in this study could represent discontinuous epitopes or mimotopes o f natural autoantigens. Also, they could be present in still-unknown p roteins involved in AITP pathogenesis. (C) 1998 Academic Press.