The main function of IL-2 is to promote the development of T regulatory cells.
Based primarily on vitro studies, interleukin (IL)-2 has been considered a key growth and death factor for antigen-activated T lymphocytes. IL-2 is also essential to maintain self-tolerance, as IL-2- and IL-2 receptor-deficient mice exhibit lethal autoimmunity. The intrinsic death-sensitizing activity of IL-2 was thought to be a key mediator for apoptosis of peripheral autoreactive T cells. However, recent in vivo studies strongly favor a model whereby IL-2 controls autoimmunity through the production of CD4+CD25+ T regulatory (Treg) cells. In this setting, IL-2 is essential for expansion of Treg cells within the thymus and in peripheral neonatal-immune tissue. Thus, from being considered the primary growth factor for antigen-activated T lymphocytes, these new findings redefine the pivotal role for IL-2 as the major inducer for the developmental production of suppressive Treg cells.
Malek
Thomas R
TR
Department of Microbiology and Immunology, University of Miami School of Medicine, 1638 N.W. 10th Avenue, Room 718A, McKnight Building, Miami, FL 33136, USA. tmalek@med.miami.edu
D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology / Q000517:prevention & control; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D007376:Interleukin-2 / Q000502:physiology*; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation; D051379:Mice; D018345:Mice, Knockout; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D017493:Leukocyte Common Antigens