[Intracellular killing mechanisms of alveolar macrophages against Mycobacterium avium complex]

To clarify the intracellular killing mechanisms of alveolar macrophages against Mycobacterium avium complex, effects of cytokines on O2- and NO2- production from normal and BCG-induced alveolar macrophages were studied. Intracellular growth of M. avium complex was inhibited in the alveolar macrophages stimulated by TNF, but not IFN. Enhancement of O2- production by normal alveolar macrophages stimulated by cytokines, was associated with the inhibition of intracellular growth of M. avium complex. However, when NO2- production by the alveolar macrophages was enhanced by the stimulating of IFN or IFN+TNF, in the presence L-arginine in the culture medium, their defense activity against M. avium complex decreased.