title: Human peripheral blood T regulatory cells (Tregs), functionally primed CCR4+ Tregs and unprimed CCR4- Tregs, regulate effector T cells using FasL.
abstract: Regulatory CD25(+)CD4(+) T cells (Tregs) play an important role in the control of peripheral tolerance. In this study we demonstrate that human peripheral blood Tregs can be divided into two distinct populations based on the expression of CCR4. The majority ( approximately 75%) of freshly isolated Tregs express CCR4 and presumably represent memory-type Tregs. Interestingly, CCR4(-) Tregs require anti-CD3 Ab-mediated activation to acquire a regulatory activity, while CCR4(+) Tregs appear to be already primed to suppress the proliferation of CD8(+) T cells. CCR4 is also expressed on CD25(low)CD4(+) T cells (CCR4(+) non-Tregs) that mostly suppress Th1-type polarization without affecting T cell proliferation, presumably via the production of immunomodulatory cytokines like IL-10. In contrast, CCR4(+) Tregs express FasL to primarily regulate T cell proliferation via a contact-mediated process involving FasL/Fas signaling, a major regulatory pathway of T cell homeostasis. Finally, we also demonstrate that the depletion of CCR4(+) T cells leads to Th1-type polarization of CD4(+) T cells and augmentation of CD8(+) T cell responses to tumor Ags.
authors.affiliation: Laboratory of Immunology, Gerontology Research Center, National Institute on Aging, Baltimore, MD 21224, USA.
authors.forename: Dolgor
authors.initials: D
authors.lastname: Baatar
authors.forename: Purevdorj
authors.initials: P
authors.lastname: Olkhanud
authors.forename: Kenya
authors.initials: K
authors.lastname: Sumitomo
authors.forename: Dennis
authors.initials: D
authors.lastname: Taub
authors.forename: Ronald
authors.initials: R
authors.lastname: Gress
authors.forename: Arya
authors.initials: A
authors.lastname: Biragyn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016764:Cell Polarity; D053222:Fas Ligand Protein / Q000502:physiology*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D054398:Receptors, CCR4; D019707:Receptors, Chemokine / Q000032:analysis / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D018417:Th1 Cells / Q000502:physiology
chemical_list: C515354:CCR4 protein, human; C515355:Ccr4 protein, mouse; D053222:Fas Ligand Protein; D054398:Receptors, CCR4; D019707:Receptors, Chemokine; D016753:Interleukin-10