title: Expression of Helios, an Ikaros transcription factor family member, differentiates thymic-derived from peripherally induced Foxp3+ T regulatory cells.
abstract: Helios, a member of the Ikaros transcription factor family, is preferentially expressed at the mRNA level by regulatory T cells (Treg cells). We evaluated Helios protein expression using a newly generated mAb and demonstrated that it is expressed in all thymocytes at the double negative 2 stage of thymic development. Although Helios was expressed by 100% of CD4(+)CD8(-)Foxp3(+) thymocytes, its expression in peripheral lymphoid tissues was restricted to a subpopulation ( approximately 70%) of Foxp3(+) T cells in mice and humans. Neither mouse nor human naive T cells induced to express Foxp3 in vitro by TCR stimulation in the presence of TGF-beta expressed Helios. Ag-specific Foxp3(+) T cells induced in vivo by Ag feeding also failed to express Helios. Collectively, these results demonstrate that Helios is potentially a specific marker of thymic-derived Treg cells and raises the possibility that a significant percentage of Foxp3(+) Treg cells are generated extrathymically.
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Thornton
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Korty
authors.forename: Dat Q
authors.initials: DQ
authors.lastname: Tran
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Wohlfert
authors.forename: Patrick E
authors.initials: PE
authors.lastname: Murray
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Belkaid
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Shevach
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D019070:Cell Lineage; D002469:Cell Separation; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism; D006801:Humans; D051740:Ikaros Transcription Factor / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology / Q000276:immunology; 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; D014157:Transcription Factors / Q000096:biosynthesis / Q000276:immunology
chemical_list: D004268:DNA-Binding Proteins; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; C111431:IKZF2 protein, human; D014157:Transcription Factors; C491746:Zfpn1a2 protein, mouse; D051740:Ikaros Transcription Factor