The mechanism of protection from type 1 diabetes conferred by regulatory T-cells induced by oral insulin treatment of NOD mice is not well understood. We demonstrate that oral insulin feeding of NOD mice induces the function of insulin B-chain reactive CD4+ regulatory T-cells, which compete with diabetogenic effector T-cells for the recognition of insulin in NOD.Scid recipient mice. These effector T-cells become deprived of interleukin (IL)-2 and interferon (IFN)-gamma and are unable to expand and migrate to the pancreas. Type 1 diabetes-protective splenic regulatory T-cells secrete relatively little transforming growth factor (TGF)-beta1, suggesting that TGF-beta may not contribute to the inactivation of effector T-cells in NOD.Scid recipients. The observed preferential infiltration of insulin-reactive regulatory T-cells rather than effector T-cells in the pancreas results in a nondestructive insulitis that correlates with an increased intrapancreatic expression of macrophage inflammatory protein-1beta. Thus, oral insulin therapy overcomes a deficiency in regulatory T-cells and protects against type 1 diabetes by inducing insulin B-chain reactive regulatory T-cells to block cytokine secretion and migration of diabetogenic effector T-cells to the pancreas. Our data emphasize that continuous oral insulin feeding over a prolonged period is required to prevent type 1 diabetes.
Insulin B-chain reactive CD4+ regulatory T-cells induced by oral insulin treatment protect from type 1 diabetes by blocking the cytokine secretion and pancreatic infiltration of diabetogenic effector T-cells.
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I Bergerot, G A Arreaza, M J Cameron, M D Burdick, R M Strieter, S W Chensue, S Chakrabarti, T L Delovitch; Insulin B-chain reactive CD4+ regulatory T-cells induced by oral insulin treatment protect from type 1 diabetes by blocking the cytokine secretion and pancreatic infiltration of diabetogenic effector T-cells.. Diabetes 1 September 1999; 48 (9): 1720–1729. https://doi.org/10.2337/diabetes.48.9.1720
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