Nitric oxide synthase induction in lines of macrophages from different anatomical sites

Induction of nitric oxide synthase (iNOS) and nitric oxide (NO) production have been demonstrated using three macrophage cell lines from different anatomical sites, which had been immortalized using a rapid and convenient procedure previously described. Lysis of tumor cells presumably was caused by NO accumulation in the supernatants of cultures of the three cell lines after induction with a mixture of recombinant murine interferon gamma (rMuIFNgamma) and lipopolysaccharide (LPS). Induction by these two biological response modifiers (BRM) caused lysis of tumor cells and was repressed by addition of 1 microM (final concentration) of methyl-L-arginine (MMA) to the mixture during induction of the enzyme. Research using readily generated macrophage cell lines may facilitate clarify basic aspects of iNOS induction in these cells.