NO₂Gas and NO₂⁻Effects on Alveolar Macrophage Phagocytosis and Metabolism

The in vitro elects of nitrogen dioxide (NO2) gas and nitrite ion (NO2 -) on the rates of entry and killing of Staphylococcus epi- dermidis and Pseυdomonas aeruginosa were measured in rabbit alveolar macrophages (AM) adherent to a glass surface. The metabolism of AM was studied in shaking cell suspensions with heat-killed epi- dermidis as test particles. Both NO2 and NO2 - (10 to 15 millimols) diminish bacterial entry and intracellular killing and increase 14CO2 production from 14C-1-glucose, 14C-6-glucose and 14C-1-pyruvate. In view of the potential role of H2O2 as an intracellular bactericidal agent, the effects of NO2 and NO2 -in catalase-dependent H2O2 metabolism were studied. Both NO2 and NO2 -(>.5 mM) react with catalase: H2O2 compound 1, as judged by diminution of formate oxidation and the sensitivity of AM catalase to aminotriazole inhibition.