Abstract
Natural killer (NK) cells directly lyse tumor or viral-infected cells but also an important role for NK cell cytotoxicity in regulating the extent of immune responses is emerging. Here, we show that autologous human macrophages activated NK cell proliferation and cytokine secretion, increased expression of activating receptors, and primed NK cell cytotoxicity against susceptible target cells. Ligation of NK cell 2B4, and not NKp30 (known to be important for DC-mediated NK cell activation), is critical for this macrophage-mediated NK cell activation. Reciprocally, however, NK cells regulated macrophage activity by directly killing macrophages stimulated by high doses of LPS. Cytolysis was triggered by NKG2D recognition of stress-inducible class I major histocompatibility complex (MHC)-like ligands on macrophages: high doses of LPS induced transcription and surface expression of ULBP1, ULBP2, and ULBP3 and surface expression of constitutively transcribed MICA. Thus, these data suggest a new function for NK cell cytotoxicity in eliminating overstimulated macrophages. Additionally, these interactions define, for the first time, 2 distinct activating NK cell synapses: lytic and nonlytic. Triggering NK cell proliferation and cytokine secretion, but not cytolysis, specifically associated with synaptic accumulation of macrophage F-actin and NK cell 2B4, while macrophages were killed when NK cell F-actin and macrophage ICAM-1 accumulated around a central cluster of NK cell NKG2D/DAP10.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / immunology
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Actins / metabolism
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Antigens, CD / immunology
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Antigens, CD / metabolism
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Cell Communication / drug effects
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Cell Communication / immunology*
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Cell Proliferation* / drug effects
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Cells, Cultured
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Coculture Techniques
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Cytokines / immunology
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Cytokines / metabolism
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Histocompatibility Antigens Class I / immunology
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Histocompatibility Antigens Class I / metabolism
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Humans
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Immunity, Cellular / drug effects
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Intracellular Signaling Peptides and Proteins / immunology
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Intracellular Signaling Peptides and Proteins / metabolism
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Killer Cells, Natural / immunology*
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Killer Cells, Natural / metabolism
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Ligands
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Lipopolysaccharides / pharmacology
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Lymphocyte Activation / drug effects
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Lymphocyte Activation / immunology*
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Macrophages / immunology*
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Macrophages / metabolism
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Membrane Glycoproteins / immunology
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Membrane Glycoproteins / metabolism
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Membrane Proteins / biosynthesis
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Membrane Proteins / immunology
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NK Cell Lectin-Like Receptor Subfamily K
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Natural Cytotoxicity Triggering Receptor 3
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Receptors, Immunologic / biosynthesis
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Receptors, Immunologic / immunology
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Receptors, Immunologic / metabolism
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Receptors, Natural Killer Cell
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Signaling Lymphocytic Activation Molecule Family
Substances
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Actins
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Antigens, CD
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CD244 protein, human
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Cytokines
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HCST protein, human
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Histocompatibility Antigens Class I
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Intracellular Signaling Peptides and Proteins
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KLRK1 protein, human
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Ligands
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Lipopolysaccharides
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Membrane Glycoproteins
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Membrane Proteins
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NCR3 protein, human
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NK Cell Lectin-Like Receptor Subfamily K
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Natural Cytotoxicity Triggering Receptor 3
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Receptors, Immunologic
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Receptors, Natural Killer Cell
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Signaling Lymphocytic Activation Molecule Family