Non-obese diabetic (NOD) mice display enhanced immune responses and prolonged survival of lymphoid cells

We report that lymphoid cells originating from the non-obese diabetic (NOD) autoimmune prone mouse strain are resistant to several signals known to induce programmed cell death. In vitro culturing of lymphoid cells of splenic or lymph node origin showed that B cells and T cells of both CD4+ and CD8+ phenotypes from NOD mice display extended survival in vitro. By cytofluorimetric analysis, immature CD4+ CD8+ NOD thymocytes were shown to partially resist in vivo treatment with corticosteroids. Finally, immunization with protein antigens induced enhanced and prolonged immune responses in NOD mice compared with normal C57BL/6, BALB/c, and C3H/Tif control mice. We conclude that the NOD mouse displays a defect in the mechanism(s) mediating programmed cell death in T and B lymphocytes. These findings provide a novel explanation for the B cell aberrations observed in the NOD mouse and may have implications for the understanding of the autoimmune pathogenesis in this mouse strain.