INTERACTION BETWEEN MYCOBACTERIUM-AVIUM AND HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) IN BRONCHOALVEOLAR MACROPHAGES OF NORMAL AND HIV-1-INFECTED SUBJECTS

Bronchoalveolar lavage (BAL) macrophages from patients with symptomatic or asymptomatic HIV-1 infections were obtained, and their ability to restrict in vitro the growth of an AIDS-associated strain of Mycobacterium avium was compared with cells obtained from normal volunteers. BAL macrophage populations from HIV-1-infected subjects (symptomatic or asymptomatic) spontaneously released significant amounts of IL-6, IL-1 beta, and TNF-alpha, whereas BAL macrophages from normal volunteers released very low amounts of these cytokines. Phagocytosis of M. avium was shown to be similar in both HIV-1-infected subjects and in control subjects. BAL macrophages from HIV-1-infected subjects released significantly greater quantities of IL-6, IL-1 beta, and TNF-alpha than did cells from normal volunteers upon M. avium ingestion. Growth of M. avium was similar in BAL macrophages from all three subject groups. Finally, BAL macrophages from normal volunteers were obtained, and these cells were doubly infected with a macrophage tropic isolate of HIV-1 at a low multiplicity of infection and with an AIDS-associated strain of M. avium. There were no significant differences in cytokine release by cells co-infected with M. avium and HIV-1 and cells infected with M. avium alone. The growth of mycobacteria and the viral replication in doubly infected cells were compared with those in cells infected with only one of the pathogens, and it was shown that HIV-1 infection had no significant effect on M. avium growth. However, viral replication in the later stages of in vitro infections was significantly augmented in BAL macrophages co-infected with M. avium, suggesting that mycobacterial phagocytosis and growth may act as important co-factors for HIV-1 replication.