title: Induction of nitrite/nitrate synthesis in murine macrophages by BCG infection, lymphokines, or interferon-gamma.
abstract: Macrophage synthesis of nitrite and nitrate after activation by BCG infection or by treatment in vitro with both T cell-derived (lymphokines (LK) or recombinant murine interferon-gamma (IFN-gamma] and bacterial (lipopolysaccharide (LPS) and heat-killed bacillus Calmette-Guerin (hk BCG] agents was studied by using macrophages from C3H/He and C3H/HeJ mice. Spleen and peritoneal macrophages isolated from BCG-infected donors that were producing nitrate continued to synthesize nitrite and nitrate in culture. LPS treatment in vitro (25 or 50 micrograms/ml) additionally increased this nitrite/nitrate synthesis. Thioglycolate-elicited macrophages from non-infected C3H/HeJ mice treated with LK also produced nitrite/nitrate, and concurrent LPS (0.1 to 50 micrograms/ml) treatment resulted in enhanced synthesis. Recombinant IFN-gamma also stimulated nitrite/nitrate synthesis by C3H/He and CeH/HeJ macrophages as did LPS (C3H/He only) and hk BCG. When given concurrently with either LPS or hk BCG, IFN-gamma enhanced C3H/He and C3H/HeJ macrophage nitrite/nitrate synthesis over that produced by macrophages treated with either LPS or hk BCG alone. Macrophages activated in vitro exhibited a 4 to 12 hr lag time before engaging in nitrite/nitrate synthesis, which then proceeded for 36 to 42 hr at linear rates. Daily medium renewal did not alter the synthesis kinetics but increased the total amount of nitrite/nitrate produced. Nitrate and nitrite were stable under the conditions of culture and when added did not influence additional macrophage synthesis. Taken together, these results indicate that T cell lymphokines and IFN-gamma are powerful modulators of macrophage nitrite/nitrate synthesis during BCG infection and in vitro, and nitrite/nitrate synthesis appears to be common property of both primed and fully activated macrophage populations.
mesh_terms: D000818:Animals; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008222:Lymphokines / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D009163:Mycobacterium bovis / Q000276:immunology; D009566:Nitrates / Q000096:biosynthesis*; D009573:Nitrites / Q000096:biosynthesis*; D013601:T-Lymphocytes / Q000502:physiology; D013997:Time Factors; D014376:Tuberculosis / Q000276:immunology*
chemical_list: D008070:Lipopolysaccharides; D008222:Lymphokines; D009566:Nitrates; D009573:Nitrites; D007371:Interferon-gamma