title: Ex vivo isolation and characterization of CD4(+)CD25(+) T cells with regulatory properties from human blood.
abstract: It has been known for years that rodents harbor a unique population of CD4(+)CD25(+) "professional" regulatory/suppressor T cells that is crucial for the prevention of spontaneous autoimmune diseases. Here we demonstrate that CD4(+)CD25(+)CD45RO(+) T cells (mean 6% of CD4(+) T cells) are present in the blood of adult healthy volunteers. In contrast to previous reports, these CD4(+)CD25(+) T cells do not constitute conventional memory cells but rather regulatory cells exhibiting properties identical to their rodent counterparts. Cytotoxic T lymphocyte-associated antigen (CTLA)-4 (CD152), for example, which is essential for the in vivo suppressive activity of CD4(+)CD25(+) T cells, was constitutively expressed, and remained strongly upregulated after stimulation. The cells were nonproliferative to stimulation via their T cell receptor for antigen, but the anergic state was partially reversed by interleukin (IL)-2 and IL-15. Upon stimulation with allogeneic (but not syngeneic) mature dendritic cells or platebound anti-CD3 plus anti-CD28 the CD4(+)CD25(+) T cells released IL-10, and in coculture experiments suppressed the activation and proliferation of CD4(+) and CD8(+) T cells. Suppression proved IL-10 independent, yet contact dependent as in the mouse. The identification of regulatory CD4(+)CD25(+) T cells has important implications for the study of tolerance in man, notably in the context of autoimmunity, transplantation, and cancer.
authors.affiliation: Department of Dermatology, University of Erlangen-Nuremberg, Hartmannstrasse 14, 91052 Erlangen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Dieckmann
authors.forename: H
authors.initials: H
authors.lastname: Plottner
authors.forename: S
authors.initials: S
authors.lastname: Berchtold
authors.forename: T
authors.initials: T
authors.lastname: Berger
authors.forename: G
authors.initials: G
authors.lastname: Schuler
mesh_terms: D000069594:Abatacept; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis*; D060908:CTLA-4 Antigen; D002469:Cell Separation; D006801:Humans; D007108:Immune Tolerance; D018796:Immunoconjugates; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000378:metabolism; D008213:Lymphocyte Activation; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D015704:CD4 Antigens; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D015375:Receptors, Interleukin-2; D016753:Interleukin-10; D000069594:Abatacept