NO2Gas and NO2-Effects on Alveolar Macrophage Phagocytosis and Metabolism

Abstract

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.