Immunology and Infectious Diseases Analysis of in Vivo Role of -Fodrin Autoantigen in Primary Sjögren’s Syndrome

The -fodrin N-terminal portion (AFN) autoantigen mediates in vivo immunoregulation of autoimmune responses in primary Sjögren’s syndrome (SS). We further examined this process and found that cleav-age products of AFN were frequently detected in the salivary gland duct cells of SS patients. In in vitro studies using human salivary gland HSY cells, anti-Fas-induced apoptosis resulted in specific cleavage of -fodrin into the 120-kd fragment, in association of -fodrin with -calpain, and activation of caspase 3. Significant proliferative responses against FN au-toantigen were observed in the peripheral blood mononuclear cells (PBMCs) from SS patients with higher pathological score (grade 4) and with short duration from onset (within 5 years). In vivo roles o