Modulating autoimmune responses to GAD inhibits disease progression and prolongs islet graft survival in diabetes-prone mice

In nonobese diabetic (NOD) mice, β-cell reactive T-helper type 1 (Th1) responses develop spontaneously and gradually spread, creating a cascade of responses that ultimately destroys the β-cells. The diversity of the autoreactive T-cell repertoire creates a major obstacle to the development of therapeutics. We show that even in the presence of established Th1 responses, it is possible to induce autoantigen-specific anti-inflammatory Th2 responses. Immune deviation of T-cell responses to the β-cell autoantigen glutamate decarboxylase (GAD65), induced an active form of self-tolerance that was associated with an inhibition of disease progression in prediabetic mice and prolonged survival of syngeneic islet grafts in diabetic NOD mice. Thus, modulation of autoantigen-specific Th1/Th2 balances may provide a minimally invasive means of downregulating established pathogenic autoimmune responses.