Cytolytic lymphocytes against pancreatic islet cells in diabetic BB rats

The BB rats have a high propensity to develop spontaneous diabetes that resembles human insulin-dependent diabetes mellitus (IDDM) and represents an exciting model for the study of this disease. In diabetic BB rats it appears that immune lymphocytes directed against insulin-producing pancreatic beta cells are involved in the pathogenesis of IDDM and are responsible for the autoimmune destruction of beta cells. Several issues arise, if such effector lymphocytes are present in the BB rats: (1) are they cytotoxic specifically toward islet cells? and (2) is their cytotoxicity restricted by the major histocompatibility complex (MHC) of the islet cell target? To answer these questions we have sought to isolate in vitro, from acutely diabetic BB rats, cytotoxic lymphocytes, which exhibit specific cytotoxity toward islet cells.