title: Distinct subsets of FoxP3+ regulatory T cells participate in the control of immune responses.
abstract: Expression of the transcription factor FoxP3 is the hallmark of regulatory T cells that play a crucial role in dampening immune responses. A comparison of the development and phenotype of FoxP3(+) T cells in relation to the expression of conventional MHC molecules facilitated the identification of several distinct lineages of naive and effector/memory populations of Foxp3(+) T cells. One subpopulation of effector/memory Foxp3(+) T cells develops in the thymic medulla, whereas the second is thymic independent. Both lineages display a distinct activated phenotype, undergo extensive steady-state proliferation, home to sites of acute inflammation, and are unique in their capacity to mediate Ag-nonspecific suppression of T cell activation directly ex vivo. Effector FoxP3(+) T cells may act as a sentinel of tolerance, providing a first line of defense against potentially harmful responses by rapidly suppressing immunity to peripheral self-Ags.
authors.affiliation: Cellular Immunology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Geoffrey L
authors.initials: GL
authors.lastname: Stephens
authors.forename: John
authors.initials: J
authors.lastname: Andersson
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Shevach
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D051858:Forkhead Transcription Factors / Q000096:biosynthesis* / Q000502:physiology; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000502:physiology; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000502:physiology; D016130:Immunophenotyping; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II