title: Human CD4+ regulatory T cells express lower levels of the IL-7 receptor alpha chain (CD127), allowing consistent identification and sorting of live cells.
abstract: Although quantitative identification and viable enrichment of natural regulatory T cells (T-regs) in humans are problematic, such steps would greatly facilitate the analysis of these cells in disease states. In an attempt to identify markers that are sensitive and specific for human T-regs, we analyzed the expression of fourteen intracellular and cell surface markers on human CD4(+) cells. Many markers were partially selective for CD25(hi) T-regs, but consistent and specific discrimination of functional T-regs was only made possible by focus on CD127, the alpha chain of the IL-7 receptor. Although most CD4(+) human T cells express CD127, T-regs exhibiting suppressive activity in vitro display distinctly lower surface expression of this marker, irrespective of their level of CD25 expression. Sorted cells with the surface phenotype CD4(+)CD25(+)CD127(low) had higher levels of intracellular FOXP3 and CTLA-4 and, as determined by functional assays, were suppressive, hypoproliferative, and poorly responsive to TCR signaling. The CD4(+)CD25(+)CD127(low) phenotype was also found to be characteristic of T-regs found in mice and in rhesus macaques. This surface phenotype should allow for quantitative studies of regulatory T cells in disease states as well as for enrichment of live regulatory T cells for functional analyses and/or expansion in vitro.
authors.affiliation: Division of Experimental Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Hartigan-O'Connor
authors.forename: Chungkee
authors.initials: C
authors.lastname: Poon
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sinclair
authors.forename: Joseph M
authors.initials: JM
authors.lastname: McCune
mesh_terms: D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002469:Cell Separation; D002470:Cell Survival / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D053699:Interleukin-7 Receptor alpha Subunit / Q000096:biosynthesis* / Q000235:genetics; D008213:Lymphocyte Activation / Q000276:immunology; D008253:Macaca mulatta; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D053699:Interleukin-7 Receptor alpha Subunit