Cytotoxicity of MHC antisera against rat islets: detection by release of 51Cr and leakage of hormones.

Antisera directed to major histocompatibility complex (MHC) antigens are able to mediate complement-dependent cytotoxicity against rat islets of Langerhans. This cytotoxic action was detected by the release of 51Cr from prelabeled islets or by the loss of glucagon, but beta-cell damage as measured by insulin leakage was less pronounced. In addition, MHC antigens were demonstrated on dispersed islet cells by indirect immunofluorescence. These results suggest that islet cells bear MHC antigens and that antibodies directed to these antigens can mediate a complement-dependent cytotoxic reaction against islets of Langerhans.