NO EVIDENCE FOR SEROLOGICAL AUTOIMMUNITY TO ISLET CELL HEAT-SHOCK PROTEINS IN INSULIN-DEPENDENT DIABETES

Recent studies in nonobese diabetic mice have implicated the autoimmune destruction of pancreatic islet cells with immunity to a beta-cell protein cross-reactive to Mycobacterium tuberculosis heat shock protein 65 (hsp 65). Therefore, our studies examined serological immunity ot islet cell h sp in humans with insulin-dependent diabetes (IDD). Heat shock of human islet cells in vitro markedly increased the synthesis of proteins of 72,000, 75,000, and 90,000 M(r). No autoantibodies reactive to these hsp, nor to the constituently expressed islet cell hsp 65 protein (identified as 60,000 M(r)) were observed in IDD patients. The islet cell 64,000-M(r) autoantigen and hsp 65 proteins were physiologically and immunocompetitively distinct. These experiments do not support the hypothesis that IDD in humans is associated with autoimmunity to islet cell heat shock proteins.