Regulatory T cells exert checks and balances on self tolerance and autoimmunity

Immunological self tolerance is maintained at least in part by regulatory T (T-reg) cells that actively and dominantly control potentially hazardous self-reactive T cells in the periphery. Antigens that stimulate self-reactive T cells may also activate natural T-reg cells, thereby maintaining dominant self tolerance. Conversely, genetic anomalies or environmental agents that specifically or predominantly affect T-reg cells cause or predispose to autoimmunity. With recent advances in our understanding of T-reg cell development in the thymus and periphery and the molecular mechanism of T-reg cell-mediated suppression, new ways of treating immunological diseases by targeting T-reg cells at the cellular and molecular levels are envisaged.