Retroviruses and diabetes in animal models: hypotheses for the induction of the disease.

This review examines the association between retroviruses and diabetes in the mouse model, the role of retroviruses in the pathogenesis of Type 1 diabetes and the mechanisms by which retroviruses can induce an autoimmune reaction. Three putative mechanisms are considered: the expression of retroviral protein(s) on the beta-cell surface as the first step in immune response against beta cells; the homology of a retroviral product with a self antigen inducing a cross-reacting autoimmune response (molecular mimicry); and a retroviral product showing homology with interleukin-2 and inducing T-cell activation against beta-cell antigens and loss of tolerance. These findings are discussed for their possible implications in the pathogenesis of human Type 1 diabetes.