Release of reactive nitrogen intermediates and reactive oxygen intermediates from mouse peritoneal macrophages. Comparison of activating cytokines and evidence for independent production.

Abstract

The capacity of 12 cytokines to induce NO2- or H2O2 release from murine peritoneal macrophages was tested by using resident macrophages, or macrophages elicited with periodate, casein, or thioglycollate broth. Elevated H2O2 release in response to PMA was observed in resident macrophages after a 48-h incubation with IFN-gamma, TNF-alpha, TNF-beta, or CSF-GM. Of these, only IFN-gamma induced substantial NO2- secretion during the culture period. The cytokines inactive in both assays under the conditions tested were IL-1 beta, IL-2, IL-3, IL-4, IFN-alpha, IFN-beta, CSF-M, and transforming growth factor-beta 1. Incubation of macrophages with IFN-gamma for 48 h in the presence of LPS inhibited H2O2 production but augmented NO2- release, whereas incubation in the presence of the arginine analog NG-monomethylarginine inhibited NO2- release but not H2O2 production. Although neither TNF-alpha nor TNF-beta induced NO2- synthesis on its own, addition of either cytokine together with IFN-gamma increased macrophage NO2- production up to six-fold over that in macrophages treated with IFN-gamma alone. Moreover, IFN-alpha or IFN-beta in combination with LPS could also induce NO2- production in macrophages, as was previously reported for IFN-gamma plus LPS. These data suggest that: 1) tested as a sole agent, IFN-gamma was the only one of the 12 cytokines capable of inducing both NO2- and H2O2 release; 2) the pathways leading to secretion of H2O2 and NO2- are independent; 3) either IFN-gamma and TNF-alpha/beta or IFN-alpha/beta/gamma and LPS can interact synergistically to induce NO2- release.