Immune attack on pancreatic islet transplants in the spontaneously diabetic BioBreeding/Worcester (BB/W) rat is not MHC restricted.

Spontaneous diabetes mellitus in the BB/W rat is preceded by lymphocytic insulitis that destroys pancreatic beta cells. Cultured pancreatic islets and adrenal cortex from inbred rats of variable MHC were transplanted to RT1/u BB/W rats without allograft rejection. Islet grafts from RT1/u and non-RT1/u rats evidenced lymphocytic insulitis in BB/W recipients that became diabetic or evidenced lymphocytic insulitis within endogenous islets. These findings suggest that BB immune insulitis is not MHC restricted and may be directed against islet transplants from non-RT1/u animals.