Differential mechanisms of intracellular killing of Mycobacterium avium and Listeria monocytogenes by activated human and murine macrophages. The role of nitric oxide.

Murine peritoneal macrophages activated with interferon-gamma (IFN-gamma) produce large quantities of nitric oxide and are efficient in the killing of certain intracellular pathogens. To examine the role of this mechanism in the killing of Mycobacterium avium by murine and human macrophages, we infected mouse peritoneal macrophages and human monocyte-derived macrophages with M. avium and Listeria monocytogenes and stimulated the cells with recombinant tumour necrosis factor (TNF), granulocyte-macrophage colony-stimulating factor (GM-CSF) or IFN-gamma, in the presence or absence of N-monomethyl-L-arginine (NMA) or arginase.