Original Article Transfusion of Apoptotic -Cells Induces Immune Tolerance to -Cell Antigens and Prevents Type 1 Diabetes in NOD Mice

In vivo induction of -cell apoptosis has been demon-strated to be effective in preventing type 1 diabetes in NOD mice. Based on the notion that steady-state cell apoptosis is associated with self-tolerance and the need for develop-ing a more practical approach using apoptotic -cells to prevent type 1 diabetes, the current study was designed to investigate apoptotic -cells induced ex vivo in preventing type 1 diabetes. The NIT-1 cell line serves as a source of -cells. Apoptotic NIT-1 cells were prepared by ultraviolet B (UVB) irradiation. Three weekly transfusions of UVB-irradiated NIT-1 cells (1 105/mouse) or PBS were used to determine whether transfusions of UVB-irradiated NIT-1 cells induce immune tolerance to -cell antigens in vivo and prevent type 1 diabetes. The suppression of anti–-cell antibodies, polarization of T-helper (Th) cells, and induc