title: Synergistic induction of cytotoxicity in macrophages by murine interferon-gamma and biological response modifiers derived from microorganisms.
abstract: The ability of recombinant murine interferon-gamma (rMuIFN-gamma) to activate murine macrophages with or without several biological response modifiers (BRM), including synthetic muramyl dipeptide derivatives (MDPs), was investigated. Mouse peritoneal macrophages were activated by rMuIFN-gamma alone to the cytostatic state, but not the cytolytic state. Other BRM as well as bacterial lipopolysaccharide (LPS), including a lyophilized preparation of an attenuated strain of Streptococcus hemolyticus, a cell wall skeleton of bacillus Calmette-Guerin and synthetic MDPs, were highly active in generating the synergism with rMuIFN-gamma. Macrophages were endowed with the cytolytic activities by combinations of rMuIFN-gamma and MDP-Lys(L18); the combination of 100 U/ml of rMuIFN-gamma with 10 ng/ml of MDP-Lys(L18) was sufficient to induce cytolytic activities in macrophages. The synergism was observed when the macrophages primed with rMuIFN-gamma were treated with LPS or MDP-Lys(L18), but not when the sequence of treatment was reversed. The cytotoxicity of macrophages induced by rMuIFN-gamma with MDP-Lys(L18) was suppressed by priming with MDP-Lys(L18). The suppressive effect was also observed by priming with LPS in combinations of rMUIFN-gamma and LPS. The reason for the suppression of macrophage activation by priming with LPS and MDP-Lys(L18) is at present unknown.
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology*; D000230:Adenocarcinoma / Q000473:pathology; D000818:Animals; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D007371:Interferon-gamma / Q000008:administration & dosage / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009163:Mycobacterium bovis; D010529:Peritoneal Cavity; D013291:Streptococcus
chemical_list: D008070:Lipopolysaccharides; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D007371:Interferon-gamma