Anti-CD3 F(ab′)2 administration diminished the T cell response in NOD mice. Lymphocytes isolated from pancreatic draining lymph nodes of anti-CD3 F(ab′)2-treated NOD mice or the controls 3 weeks after antibody treatment were reacted with recombinant mouse GAD65 protein (GAD65), 500–585 part of GAD65 (GAD500–585), porcine insulin, concanavalin, or myelin basic protein, and the cells were incubated with 0.5μCi of [3H]thymidine. Proliferation was determined by [3H]thymidine uptake. Data are expressed as stimulation indices (SI) ± SD of the mean from four mice with the background of 1249–3914 cpm, tested in triplicate.*P < 0.05, **P < 0.01 as compared with the control counterparts.