Insulin-dependent diabetes mellitus: the hypothesis of molecular mimicry between islet cell antigens and microorganisms.

Insulin-dependent diabetes mellitus (IDDM) in humans and the non-obese diabetic mouse is a polygenic disease, resulting from an autoimmune destruction of the insulin-secreting pancreatic beta cells. At least in NOD mice, the process is mediated through a T helper 1-cell-mediated cytotoxicity pathway. Although there is much circumstantial evidence to suggest that IDDM is environmentally induced, recent studies support the possibility that the inductive event involves cross-reactive immune responses to antigenic epitopes acting as molecular mimics between microbial proteins and autoantigens expressed by pancreatic insulin-secreting beta cells. The following article reviews the evidence for this concept.