NRAMP1-or cytokine-induced bacteriostasis of Mycobacterium avium by mouse macrophages is independent of the respiratory burst

Restriction of the growth of Mycobacterium avium was studied in wild-type and p47(phox)-deficient macrophages. The ability of gamma interferon and tumour necrosis factor alpha to induce anti mycobacteria I activity in bone-marrow-derived macrophages or the expression of the NRAMP1-mediated resistance to M. avium were not affected by the deficiency in p47(phox). The addition of exogenous iron increased mycobacterial growth in macrophages expressing a functional NRAMP1 protein or a mutant NRAMP1 protein. Reactive oxygen species are therefore not involved in the constitutive or induced anti-M. avium activities of the mouse macrophage.