title: Biological and antigenic similarities of murine interferon-gamma and macrophage-activating factor.
abstract: Murine peritoneal exudate cells (PEC) treated with murine recombinant interferon-gamma (IFN-gamma) (greater than 99% estimated purity), or concanavalin A-stimulated spleen cell supernatants developed tumoricidal properties (macrophage activation factor [MAF] activity). MAF activity was found to occur with treatments of 10 U/ml IFN-gamma, and at levels as low as 1 U/ml IFN-gamma if a second signal (5 ng/ml endotoxin) was present in the MAF assay. Endotoxin (lipopolysaccharide [LPS]) alone at these levels failed to induce MAF; induction of MAF was observed at 1,000-fold greater levels. The ability of IFN-gamma to stimulate murine PEC was species specific. Various sources of materials that displayed MAF activity, including supernatants from interleukin 2-dependent cloned cytotoxic murine T lymphocyte lines that did not display detectable antiviral activity, were neutralized by antibody raised and affinity purified against recombinant IFN-gamma. Thus, IFN-gamma, although never detectable by antiviral assays, appears to be present in many lymphokine preparations and has potent macrophage activation capability.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000276:immunology; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D007700:Kinetics; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009500:Neutralization Tests; D011817:Rabbits; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D008222:Lymphokines; D016215:Macrophage-Activating Factors; D007371:Interferon-gamma