HIV-1 and Chlamydia trachomatis restrict their respective growth but promote their survival in co-infected human macrophages

HIV-1 and Chlamydia trachomatis (CT) are two significant sexually transmitted pathogens that frequently co-infect individuals. However, the mechanisms by which these two obligate intracellular pathogens interact at the cellular level remain elusive, particularly in tissue macrophages, where persistent infections can occur. In this study, we demonstrate that CT generates inclusions in macrophages of murine and human origins. We also show that both HIV-1 and CT reciprocally restrict the growth and replication of each other within co-infected human macrophages, irrespective of whether the viral or bacterial infection is established first. Notably, the co-infection resulted in improved survival of the macrophage hosts, as the inflammatory cell death pathways induced by CT were prevented by the virus. Collectively, these findings demonstrate that HIV-1 and CT collaborate to persist in human macrophages.