Naturally arising CD25+CD4+ regulatory T cells in tumor immunity

Naturally arising regulatory T (T-R) cells, represented by CD25(+)CD4(+) T-R cells, play an essential role in maintaining immunological self-tolerance. This T cell-mediated dominant control of the immune response not only inhibits the development of autoimmune disease, but also impedes effective immuno surveillance against autologous tumor cells. Attenuation of T-R cell-mediated immune suppression can therefore evoke effective tumor immunity in otherwise nonresponsive animals. This common regulatory mechanism for autoimmunity and tumor immunity can be exploited when devising a novel immunotherapy for cancer.