Macrophage activation: synergism between hybridoma MAF and poly(I). Poly(C) delivered by liposomes.
High concentrations of a murine T cell hybridoma culture supernatant containing macrophage-activating factor (MAF) rendered resident mouse peritoneal macrophages cytotoxic for P815 mastocytoma cells. The capacity of the hybridoma-derived MAF (MAFH) to induce tumoricidal activity increased 10(3) to 10(4)-fold when the lymphokine was encapsulated into liposomes. Combinations of MAFH and poly(I) X poly(C) acted synergistically to render macrophages potently cytotoxic. Subthreshold (nonactivating) concentrations of free or liposome-encapsulated MAFH increased the potency of free poly(I) X poly(C) and liposome encapsulated poly(I) X poly(C). Either as free agent or encapsulated in liposomes, single-stranded poly(I) or poly(C) did not activate macrophages in the presence or absence of MAFH. Double-stranded poly(I) X poly(C) was thus required for macrophage activation and synergism with MAFH.
D000818:Animals; D003602:Cytotoxicity, Immunologic; D004306:Dose-Response Relationship, Immunologic; D004357:Drug Synergism; D006825:Hybridomas / Q000276:immunology; D008081:Liposomes / Q000276:immunology*; D008222:Lymphokines / Q000502:physiology*; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors; D012515:Mast-Cell Sarcoma / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D011070:Poly I-C / Q000502:physiology*
D008081:Liposomes; D008222:Lymphokines; D016215:Macrophage-Activating Factors; D011070:Poly I-C