The interaction of macrophages and bacteria: A comparative study of the induction of tumoricidal activity and of reactive nitrogen intermediates

The abilities of various bacteria to induce in a pure population of bone marrow-derived mononuclear phagocytes (BMMφ) tumoricidal activity and/or the generation of reactive nitrogen intermediates (RNI) were comparatively assessed. Interaction of (BMMφ) with bacteria led to expression of these functional activities, indicating that the organisms were recognized as foreign. As the majority of bacteria elicited in (BMMφ) either tumoricidal activity (that is maintained for days) or the production of RNI, measured by the release of nitrite (that is short-lived), it appears that the two functions are under separate control. However, both functions are inhibited or even abrogated by arginase or the l-arginine analogue, N G-monomethyl- l-arginine, suggesting that their expression is dependent on l-arginine.