title: NKp46 and NKG2D receptor expression in NK cells with CD56dim and CD56bright phenotype: regulation by histamine and reactive oxygen species.
abstract: The cytotoxicity of natural killer (NK) cells is dependent on the interaction between target cell ligands and a series of stimulatory receptors on NK cells. Two of these triggering receptors, the NKp46 natural cytotoxicity receptor (NKp46) and the major histocompatibility complex (MHC) class I-interactive NKG2D receptor, are deficiently expressed by NK cells recovered from patients with acute myeloid leukaemia (AML), but little is known regarding the regulation of NKp46 and NKG2D expression. Here we report that mononuclear and polymorphonuclear phagocytes downregulate the cell surface density of NKp46 and NKG2D on NK cells with CD56(dim) phenotype in vitro by a mechanism that is dependent on the availability of phagocyte-derived reactive oxygen species (ROS). Histamine maintained NKp46 and NKG2D expression despite the presence of inhibitory phagocytes by targeting an H2 receptor on phagocytes. By contrast, NKp46 and NKG2D expression by the CD56(bright) subset of NK cells was resistant to inhibition by phagocytes. Our findings are suggestive of a novel mechanism of relevance to the regulation of NKp46/NKG2D receptor expression. Moreover, our findings suggest that the previously reported action of histamine on NK cell-mediated killing of leukaemic cells may be related to the preservation of activatory NK-cell receptors.
authors.affiliation: Department of Virology, Göteborg University, Gothenburg, Sweden. ana.romero@microbio.gu.se
authors.forename: Ana I
authors.initials: AI
authors.lastname: Romero
authors.forename: Fredrik B
authors.initials: FB
authors.lastname: Thorén
authors.forename: Mats
authors.initials: M
authors.lastname: Brune
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Hellstrand
mesh_terms: D017209:Apoptosis / Q000276:immunology; D019002:CD56 Antigen / Q000032:analysis*; D002478:Cells, Cultured; D015536:Down-Regulation / Q000276:immunology; D005434:Flow Cytometry; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism*; D055655:NK Cell Lectin-Like Receptor Subfamily K; D055627:Natural Cytotoxicity Triggering Receptor 1; D018375:Neutrophil Activation / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D010586:Phagocytes / Q000276:immunology; D017382:Reactive Oxygen Species / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism*; D055607:Receptors, Natural Killer Cell; D015854:Up-Regulation / Q000276:immunology
chemical_list: D019002:CD56 Antigen; C527085:KLRK1 protein, human; D008562:Membrane Glycoproteins; C112260:NCR1 protein, human; D055655:NK Cell Lectin-Like Receptor Subfamily K; D055627:Natural Cytotoxicity Triggering Receptor 1; D017382:Reactive Oxygen Species; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell; D006632:Histamine