IDDM - AN ISLET OR AN IMMUNE-DISEASE

Insulin-dependent diabetes develops as a consequence of the selective destruction of insulin-producing cells by an autoimmune reaction. Howe ver, the precise series of events which trigger anti-islet autoreactiv e T cells is still being investigated. Major issues will need to be ra ised before a comprehensive view of the anti-islet autoimmune reaction can be delineated. These include defining the primary site of activat ion of autoreactive lymphocytes and exploring hypotheses to explain th e chronicity of the diabetes process. These issues all relate with the more general dilemma of the actual role of the islets of Langerhans i n breaking self tolerance to beta-cell antigens By studying non-obese diabetic mice deprived of beta cells following a single injection of a high dose of alloxan at 3 weeks of age, we recently obtained evidence that the activation of autoreactive T cells requires the presence of target islet cells in order to develop.