Insulin dependent diabetes mellitus is a T-cell mediated autoimmune di
sease. Several beta-cell antigens, mostly non-tissue-specific, have be
en implicated in the disease process. The antigens and the autoimmune
T cells exist in healthy individuals, as do many of the genes required
for the development of diabetes. The question, then, is why and how e
xposure to undefined environmental agents activates an existing autoim
mune potential and directs it to damage the beta cells.