CD52 as both a marker and an effector molecule of T cells with regulatory action: Identification of novel regulatory T cells

Regulation of immune responses is central to an effective clearance of pathogens. An effective immune response is also necessary for preventing the development of cancer and autoimmune diseases and for maintaining homeostasis. Although the thymus is the central lymphoid organ that regulates immune responses for self-tolerance during the maturation of T cells, regulatory immune cells are still required for the proper functioning of mature immune cells in the periphery. Regulatory cells are a subpopulation of immune cells that suppress proliferation and cytokine production by other immune cells in response to antigenic stimulation. Although cells with regulatory functions have been identified in almost all of the major immune cell populations, regulatory T cells are still the dominant and most intensely studied type. Several types of regulatory T cells have been identified, including CD4+CD25+ T regulatory cells (Tregs), which are also positive for Foxp3, the master regulator of Treg development.1