Comparative studies on alveolar macrophages and polymorphonuclear leukocytes. II. The ability of guinea pig alveolar macrophages to produce H2O2.

Guinea pig alveolar macrophages (A-M0) were studied with respect ot the phagocytic metabolism: the respiratory burst and its KCN sensitivity, the ability to generate H2O2, and myeloperoxidase (MPO) activity. Only fifty percent of the O2 uptake by A-M0 samples during phagocytosis was inhibited by the addition of 1 mK KCN. Guinea pig A-M0 released H2O2 amounting to 7.7 and 12.5 nmol/min/10(7) cells upon addition of E. coli in the absence and presence of anti-E. coli antibody, respectively. Myristic acid, an effective membrane activator, induced a marked release of H2O2 amounting to 16.1 nmol/min/10(7) cells. We observed a high MPO activity in some alveolar lavage cells which contained a large number of polymorphonuclear leukocytes (PMN), but none at all in preparations containing fewer PMN. The MPO activity detected did not seem to be due to A-M0, but to the PMN contained in the preparations.