FOXP3 and diabetes mellitus: In animal models of autoimmune diabetes, BDC2.5 TCR–transgenic Tregs, which are specific for a fusion peptide between insulin C and chromogranin A, or NOD T cells engineered to express FOXP3 and the BDC2.5 T cell receptor (TCR) suppressed diabetes induced by T cells from diabetic NOD mice or BDC2.5 T effector cells (13–16).