Inhibition of human immunodeficiency type 1 virus replication in monocytic U-937 cells by superinfection with Chlamydia trachomatis.

The aim of this study was to investigate the effects of infection of monocytic cells with both the human immunodeficiency type 1 virus (HIV-1) and Chlamydia trachomatis on the replication of each pathogen. U-937 cells, chronically infected with HIV-1 (strain LaVLai), either induced to differentiate into immature macrophage-like cells by 32 pM 12-O-tetradecanol phorbol-13-acetate or uninduced, were superinfected with C. trachomatis serovar L2. Both HIV-1 infection and differentiation rendered the U-937 cells highly susceptible to C. trachomatis lytic infection. Differentiation and superinfection of HIV-1-infected cells with C. trachomatis both affected cell viability and reduced viral production in vitro. RT activity was one tenth the original value after differentiation of HIV-1-infected cells, one twentieth the original value after superinfection with C. trachomatis, and one hundredth the original value after differentiation and superinfection with C. trachomatis.