TNF-alpha-mediated multiplication of human immunodeficiency virus in chronically infected monocytoid cells by mycobacterial infection

Mycobacterial infection is a common occurrence in patients with acquired im mune deficiency syndrome. Incubation of U1, a chronically HIV-1-infected hu man promonocytic cell line, with Mycobacterium smegmatis, M. avium, M. bovi s BCG and M. tuberculosis resulted in enhancement of p24 antigen release in the supernatant, indicating that these mycobacteria could activate HIV rep lication from this cell line. The amount of p24 in the culture infected wit h M. smegmatis was higher than in cultures infected with other mycobacteria . The amounts of p24 release in cultures infected with M. avium and M. bovi s BCG were intermediate. M. tuberculosis slightly stimulated HIV replicatio n. The amount of TNF-alpha produced by U1 cells was correlated with the amo unt of p24 antigen release. The IL-1 beta and IL-6 levels in the supernatan t from cultures infected with all species were the same. The antibody to TN F-alpha inhibited p24 release induced by mycobacterial infections. The anti -IL-1 beta and anti-IL-6 antibodies, however, scarcely influenced stimulati on of HIV replication by mycobacterial infection. These data suggested that activation of HIV replication by mycobacteria mainly occurred by secondary release of cytokine TNF-alpha.