title: The CD16-/CD56bright subset of NK cells is resistant to oxidant-induced cell death.
abstract: Phagocyte-derived reactive oxygen species ("oxygen radicals") have been ascribed a suppressive role in immunoregulation by inducing dysfunction and apoptotic cell death in lymphocytes. Earlier studies show that human NK cells are exceptionally sensitive to oxygen radical-induced apoptosis and functional inhibition. Two subsets of human CD56(+) NK cells have been identified: the highly cytotoxic CD56(dim) cells which constitute >90% of NK cells in peripheral blood, and the less cytotoxic but efficiently cytokine-producing CD56(bright) cells. In this study, we demonstrate that the CD56(bright) subset of NK cells, in contrast to CD56(dim) cells, remains viable and functionally intact after exposure to phagocyte-derived or exogenously added oxygen radicals. The resistance of CD56(bright) cells to oxidative stress was accompanied by a high capacity of neutralizing exogenous hydrogen peroxide, and by a high cell-surface expression of antioxidative thiols. Our results imply that CD56(bright) NK cells are endowed with an efficient antioxidative defense system that protects them from oxygen radical-induced inactivation.
authors.affiliation: Department of Infectious Medicine, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden.
authors.forename: Fredrik B
authors.initials: FB
authors.lastname: Thorén
authors.forename: Ana I
authors.initials: AI
authors.lastname: Romero
authors.forename: Svante
authors.initials: S
authors.lastname: Hermodsson
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Hellstrand
mesh_terms: D017209:Apoptosis / Q000276:immunology*; D019002:CD56 Antigen / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000276:immunology / Q000633:toxicity; D007371:Interferon-gamma / Q000276:immunology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D016877:Oxidants / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000276:immunology* / Q000633:toxicity; D017452:Receptors, IgG / Q000276:immunology / Q000378:metabolism*
chemical_list: D019002:CD56 Antigen; D016877:Oxidants; D017382:Reactive Oxygen Species; D017452:Receptors, IgG; D007371:Interferon-gamma; D006861:Hydrogen Peroxide