Immune suppression and skin cancer development: regulation by NKT cells

Ultraviolet (UV) radiation is carcinogenic and immunosuppressive. UV-induce d immune suppression is mediated by antigen-specific T cells, which can tra nsfer suppression to normal recipients. These cells are essential for contr olling skin cancer development in the UV-irradiated host and in suppressing other immune responses, such as delayed-type hypersensitivity. Despite the ir importance in skin cancer development, their exact identity has remained elusive. We show here that natural killer T cells from UV-irradiated donor mice function as suppressor T cells and play a critical role in regulating the growth of UV-induced skin cancers and suppressing adaptive immune resp onses in vivo.