title: TCR repertoire and Foxp3 expression define functionally distinct subsets of CD4+ regulatory T cells.
abstract: Despite extensive research efforts to characterize peripheral regulatory T (T(reg)) cells expressing transcription factor Foxp3, their subset complexity, phenotypic characteristics, TCR repertoire and Ag specificities remain ambiguous. In this study, we identify and define two subsets of peripheral T(reg) cells differing in Foxp3 expression level and TCR repertoires. T(reg) cells expressing a high level of Foxp3 and TCRs not used by naive CD4(+) T cells present a stable suppressor phenotype and dominate the peripheral T(reg) population in unmanipulated mice. The second T(reg) subset, expressing a lower level of Foxp3 and using TCRs shared with naive CD4(+) T cells constitutes a small fraction of all T(reg) cells in unmanipulated mice and enriches T(reg) population with the same Ag specificities as expressed by activated/effector T cells. This T(reg) subset undergoes extensive expansion during response to Ag when it becomes a major population of Ag-specific T(reg) cells. Thus, T(reg) cells expressing TCRs shared with naive CD4(+) T cells have a flexible phenotype and may down-regulate Foxp3 expression which may restore immune balance at the conclusion of immune response or convert these cells to effector T cells producing inflammatory cytokines.
authors: Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta, GA 30912, USA.
authors: Michal
authors: M
authors: Kuczma
authors: Iwona
authors: I
authors: Pawlikowska
authors: Magdalena
authors: M
authors: Kopij
authors: Robert
authors: R
authors: Podolsky
authors: Grzegorz A
authors: GA
authors: Rempala
authors: Piotr
authors: P
authors: Kraj
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015704:CD4 Antigens / Q000008:administration & dosage / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics*; D005786:Gene Expression Regulation / Q000276:immunology*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D016130:Immunophenotyping; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018448:Models, Immunological; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D016192:Resting Phase, Cell Cycle / Q000235:genetics / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D015704:CD4 Antigens; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D011948:Receptors, Antigen, T-Cell; D049452:Green Fluorescent Proteins