title: Natural versus adaptive regulatory T cells.
abstract: It is now well recognized that regulatory T cells (Treg) play a central role in the control of both reactivity to self-antigens and alloimmune response. Several subsets of Treg with distinct phenotypes and mechanisms of action have now been identified. They constitute a network of heterogeneous CD4+ or CD8+T cell subsets and other minor T cell populations such as nonpolymorphic CD1d-responsive natural killer T cells. Treg not only play a main role in maintaining self-tolerance and preventing autoimmune disease but can also be induced by tolerance protocols and seemed to play a key role in preventing allograft rejection, as demonstrated in many animal models. Of particular interest, in stable transplant patients, CD4+CD25+ and CD8+CD28- Treg have been recently shown to modulate immune response toward donor antigens in the indirect and direct pathway, respectively. This finding raises the possibility that such Treg also have a role in the induction or maintenance of transplant tolerance in humans.
authors.affiliation: Center for Research on Organ Transplantation, Chiara Cucchi de Alessandri e Gilberto Crespi, Mario Negri Institute for Pharmacological Research, Villa Camozzi, Ranica (Bergamo), Italy.
authors.forename: Linda
authors.initials: L
authors.lastname: Cassis
authors.forename: Sistiana
authors.initials: S
authors.lastname: Aiello
authors.forename: Marina
authors.initials: M
authors.lastname: Noris
mesh_terms: D000818:Animals; D015551:Autoimmunity / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D006085:Graft Survival; D006086:Graft vs Host Disease / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology*; D007113:Immunity, Innate / Q000502:physiology*; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D051379:Mice; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014181:Transplantation Immunology / Q000276:immunology / Q000502:physiology