title: Synergy among receptors on resting NK cells for the activation of natural cytotoxicity and cytokine secretion.
abstract: Freshly isolated, resting natural killer (NK) cells are generally less lytic against target cells than in vitro interleukin 2 (IL-2)-activated NK cells. To investigate the basis for this difference, the contribution of several receptors to activation of human NK cells was examined. Target-cell lysis by IL-2-activated NK cells in a redirected, antibody-dependent cytotoxicity assay was triggered by a number of receptors. In contrast, cytotoxicity by resting NK cells was induced only by CD16, and not by NKp46, NKG2D, 2B4 (CD244), DNAM-1 (CD226), or CD2. Calcium flux in resting NK cells was induced with antibodies to CD16 and, to a weaker extent, antibodies to NKp46 and 2B4. Although NKp46 did not enhance CD16-mediated calcium flux, it synergized with all other receptors. 2B4 synergized with 3 other receptors, NKG2D and DNAM-1 each synergized with 2 other receptors, and CD2 synergized with NKp46 only. Resting NK cells were induced to secrete tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma), and to kill target cells by engagement of specific, pair-wise combinations of receptors. Therefore, natural cytotoxicity by resting NK cells is induced only by mutual costimulation of nonactivating receptors. These results reveal distinct and specific patterns of synergy among receptors on resting NK cells.
authors.affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, 12441 Parklawn Dr, Rockville, MD 20852, USA.
authors.forename: Yenan T
authors.initials: YT
authors.lastname: Bryceson
authors.forename: Michael E
authors.initials: ME
authors.lastname: March
authors.forename: Hans-Gustaf
authors.initials: HG
authors.lastname: Ljunggren
authors.forename: Eric O
authors.initials: EO
authors.lastname: Long
mesh_terms: D015703:Antigens, CD / Q000502:physiology; D020013:Calcium Signaling; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic; D058851:GPI-Linked Proteins; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000502:physiology; D055627:Natural Cytotoxicity Triggering Receptor 1; D020239:Receptor Cross-Talk; D017452:Receptors, IgG / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology*; D000071176:Signaling Lymphocytic Activation Molecule Family
chemical_list: D015703:Antigens, CD; C084093:CD244 protein, human; D016207:Cytokines; C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; C112260:NCR1 protein, human; D055627:Natural Cytotoxicity Triggering Receptor 1; D017452:Receptors, IgG; D011971:Receptors, Immunologic; D000071176:Signaling Lymphocytic Activation Molecule Family