title: Interleukin-10-induced CD8 cell proliferation.
abstract: Interleukin (IL)-10, a product of T helper 2 (Th2) lymphocytes, has been shown to be an important regulator of lymphoid and myeloid cells, inhibiting mitogen, peptide and alloantigen-induced T-cell proliferation and IL-2 production. The microenvironment at the time of cell activation, notably the presence or absence of cytokines such as IL-10, interferon-gamma (IFN-gamma) and IL-2, is believed to determine the lineage and magnitude of cell-mediated responses. In this study, we show that recombinant human IL-10 (rhIL-10) exerts a dose-dependent inhibitory effect on human peripheral blood mononuclear cells stimulated in vitro, when these cells have not previously been exposed to rhIL-10. Furthermore, incubation of these cells with high doses of rhIL-10, either before or at the time of activation, results in inhibition which is followed several days later by the emergence of a population of CD8 positive cells. This rhIL-10-responsive CD8, positive cell population still emerges even when the cells are washed following incubation with rhIL-10 prior to cell activation. Using purified CD8 populations this was shown to be a direct action of rhIL-10 on CD8 cells and not via CD4 positive cells and monocytes. This finding was only observed when cells were activated with a cross-linking anti-CD3 antibody and not when activated with phorbol-12-mystrate-13-acetate (PMA) and calcium ionophore (CaIon), suggesting that the effect is mediated through cell-surface receptors. Analysis of CD8 positive clones reveal production of Tc2 patterns of cytokines and reduced cell cytotoxicity to allogeneic, natural killer and lymphokine activated cell targets.
authors.affiliation: Department of Pathology and Microbiology, University of Bristol,UK
authors.forename: A W
authors.initials: AW
authors.lastname: Rowbottom
authors.forename: M A
authors.initials: MA
authors.lastname: Lepper
authors.forename: R J
authors.initials: RJ
authors.lastname: Garland
authors.forename: C V
authors.initials: CV
authors.lastname: Cox
authors.forename: E G
authors.initials: EG
authors.lastname: Corley
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017252:CD3 Complex / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology*; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000276:immunology; D007476:Ionophores / Q000494:pharmacology; D008213:Lymphocyte Activation; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D007155:Immunologic Factors; D007476:Ionophores; D016753:Interleukin-10; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013755:Tetradecanoylphorbol Acetate