Interferon gamma-treated human macrophages display enhanced cytolysis and generation of reactive oxygen metabolites but reduced ingestion upon Fc receptor triggering
Abstract
Human monocyte-derived macrophages treated with recombinant IFN-gamma (rIFN-gamma) and control cells were assessed for three distinct effector functions, all mediated by Fc receptors. rIFN-gamma-primed macrophage displayed markedly reduced phagocytosis of IgG antibody-coated erythrocytes. In contrast, antibody-dependent cytotoxicity towards IgG-antibody-coated erythrocytes and IgG-antibody-coated erythrocyte-induced generation of reactive oxygen metabolite production were increased. The decreased phagocytosis was observed microscopically, as well as in a spectrometric and a radiometric phagocytosis assay. Evidence is presented that the observed impairment in phagocytosis is not the result of increased extracellular lysis or intracellular catabolism of IgG-antibody-coated erythrocytes and that it is not observed with particles ingested in an Fc receptor-independent manner. Enhanced production of reactive oxygen metabolites was detected most clearly by measurement of luminol-dependent chemiluminescence. Antibody-dependent cellular cytotoxicity was shown to proceed also under conditions impeding phagocytosis, and rIFN-gamma-treated macrophage exerted enhanced antibody-dependent cellular cytotoxicity under these conditions too. In ...Continue Reading
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Antibody-Dependent Cell Cytotoxicity
Antibody-dependent cellular toxicity refers to the lysis of a target cell by a non-sensitized effector cell of the immune system as a result of antibodies binding to the target cell membrane and engaging the Fc receptors on the immune effector cells. Find the latest research on antibody-dependent cellular toxicity here.