PRODUCTION OF TUMOR-NECROSIS-FACTOR-ALPHA BY RESIDENT AND ACTIVATED MURINE MACROPHAGES

Alveolar macrophages (Amphis), resident peritoneal macrophages (RPmphis), and thioglycolate-elicited peritoneal macrophages (TGPmphis) were isolated from C57BL/6 mice and incubated with lipopolysaccharide (LPS), stimulated cell supernatant, or recombinant interferon gamma (IFN-gamma) for 24 h. Tumor necrosis factor (TNF) in cell-free supernatants was measured by enzyme-linked immunosorbent assay. Amophis incubated with 10(3) ng/ml LPS produced 50 times more TNF than RPmphis and 5 times more than TGPmphis, and LPS alone induced maximum TNF production by Amphis. Stimulated cell supernatant or recombinant IFN-gamma alone did not induce TNF production. A combination of LPS with stimulated cell supernatant or IFN-gamma had only a limited synergistic effect on TNF production by Amphis. However, both LPS and stimulated cell supernatant or recombinant IFN-gamma induced maximum TNF production by RPmphis and TGPmphis. TGPmphis showed greater sensitivity to LPS and stimulated cell supernatant or IFN-gamma with regard to TNF production than the other macrophage populations investigated.