In vitro activity of inhibitors of late stages of the replication of HIV in chronically infected macrophages

Because of the importance of macrophages in the pathogenesis of the disease caused by HIV, we inves- tigated the efficacy of various anti-HIV drugs in human primary macrophages acutely or chronically infected by this virus. The results obtained for acutely infected macro- phages show that dideoxynucleosides (AZT, ddl, and ddC), interferon-a and -y, mismatched double-stranded RNA, Tat inhibitor, phosphorothioate antisense, and in- hibitors of HIV protease, all significantly inhibit virus replication at concentrations far below those toxic for the cells. However, in macrophages in which proviral DNA is already integrated (chronically infected macrophages), only the three inhibitors of HIV protease induced significant virus inhibition at concentrations 100 or more times higher than those effective in acutely infected macro- phages. Treatment of macrophages with macrophage colony-stimulating factor does not affect the anti-HIV efficacy of protease inhibitors. These results suggest that therapeutic strategies with activity for macrophages, in- cluding inhibitors of HIV protease, are worth pursuing in patients with HIV infection. J. Leukoc. Biol. 56: 381-386; 1994.