title: In vitro killing of Entamoeba histolytica trophozoites by interferon-gamma-activated mouse macrophages.
abstract: The effect of murine interferon gamma (IFN-gamma) on macrophage activation for amoebicidal activity was examined. Peritoneal macrophages were harvested from C57BL/6 mice and preincubated with IFN-gamma and/or lipopolysaccharide (LPS). In vitro amoebicidal activity of these macrophages was determined by trypan blue exclusion test against a virulent strain of E. histolytica (IP:0682:1). It was found that in vitro amoebicidal activity was evident in macrophage monolayers treated with both IFN-gamma and LPS. Macrophages treated with IFN-gamma alone did not develop cytotoxic activity unless they were exposed to LPS as a second triggering signal. The ability of IFN-gamma to prime macrophages to respond to trigger signals of LPS and develop cytotoxicity increased with time of incubation, the highest response being observed after 24 h. There was a dose-dependent relationship between the concentrations of both IFN-gamma and LPS used to activate macrophages and the number of dead trophozoites. These data suggest that macrophages are important in host defense against amoebiasis.
mesh_terms: D000562:Amebiasis / Q000628:therapy*; D000818:Animals; D002478:Cells, Cultured; D004748:Entamoeba histolytica / Q000276:immunology*; D004749:Entamoebiasis / Q000628:therapy*; D007167:Immunotherapy; D007371:Interferon-gamma / Q000627:therapeutic use*; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000627:therapeutic use*
chemical_list: D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D007371:Interferon-gamma