title: Production of TNF-alpha by human V gamma 9V delta 2 T cells via engagement of Fc gamma RIIIA, the low affinity type 3 receptor for the Fc portion of IgG, expressed upon TCR activation by nonpeptidic antigen.
abstract: Human lymphocytes expressing the gammadelta TCR represent a minor T cell subpopulation found in blood. The majority of these cells express Vgamma9Vdelta2 determinants and respond to nonpeptidic phosphoantigens. Several studies have shown that, in vivo, the percentage of Vgamma9Vdelta2 T cells dramatically increases during pathological infection, leading to the hypothesis that they play an important role in the defense against pathogens. However, the specific mechanisms involved in this response remain poorly understood. It has been established that Vgamma9Vdelta2 T cells display potent cytotoxic activity against virus-infected and tumor cells, thereby resembling NK cells. In this study, we show that, upon stimulation by nonpeptidic Ags, Vgamma9Vdelta2 T cells express FcgammaRIIIA (CD16), a receptor that is constitutively expressed on NK cells. CD16 appears to be an activation Ag for Vgamma9Vdelta2 T cells. Indeed, ligation of CD16 on Vgamma9Vdelta2 T cells leads to TNF-alpha production. This TNF-alpha production, which is dependent (like that induced via the TCR-CD3 complex) on the activation of the p38 and extracellular signal-regulated kinase-2 mitogen-activated protein kinases, can be modulated by CD94 NK receptors. Therefore, it appears that Vgamma9Vdelta2 T cells can be physiologically activated by two sequential steps via two different cell surface Ags: the TCR-CD3 complex and the FcgammaRIIIA receptor, which are specific cell surface Ags for T lymphocytes and NK cells, respectively. This strongly suggests that, in the general scheme of the immune response, Vgamma9Vdelta2 T cells represent an important subpopulation of cells that play a key role in the defense against invading pathogens.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 431, Microbiologie et Pathologie Cellulaire Infectieuse, Université Montpellier II, Montpellier, France. vlafont@crit.univ-montp2.fr
authors.forename: V
authors.initials: V
authors.lastname: Lafont
authors.forename: J
authors.initials: J
authors.lastname: Liautard
authors.forename: J P
authors.initials: JP
authors.lastname: Liautard
authors.forename: J
authors.initials: J
authors.lastname: Favero
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000942:Antigens, Bacterial / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D015536:Down-Regulation / Q000276:immunology; D045782:Hemiterpenes; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007141:Immunoglobulin Fc Fragments / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism / Q000502:physiology; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000276:immunology; D048370:MAP Kinase Kinase 2; D020935:MAP Kinase Signaling System / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D051920:NK Cell Lectin-Like Receptor Subfamily D; D009943:Organophosphorus Compounds / Q000276:immunology*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis* / Q000378:metabolism; D017452:Receptors, IgG / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D014443:Tyrosine / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D015703:Antigens, CD; D045782:Hemiterpenes; D007106:Immune Sera; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; C497869:KLRD1 protein, human; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D051920:NK Cell Lectin-Like Receptor Subfamily D; D009943:Organophosphorus Compounds; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha; C004809:isopentenyl pyrophosphate; D014443:Tyrosine; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases