Short Communication: Molecular Inhibition of HIV Type 1 by HIV Type 2: Effectiveness in Peripheral Blood Mononuclear Cells

ABSTRACT HIV-2 downregulates HIV-1 in human primary peripheral blood mononuclear cells (PBMCs). Although the effect of HIV-2 on HIV-1 in human CD4+ T cell lines was previously reported, the present observations with PBMCs are a necessary demonstration before considering animal model and clinical studies. Notably, the downregulation was observed with at least three phenotypically different HIV-1 proviruses and three different HIV-2 proviruses and was independent of the mode of introduction of the proviruses. HIV-2 inhibited both the production of extracellular HIV-1 p24 antigen and intracellular viral RNA, suggesting the involvement of transcriptional downmodulation. Some of the defective HIV-2 proviruses also inhibited HIV-1. In some cases, these defects were transcomplemented by the corresponding HIV-1 gene products, emphasizing cross-regulation between the two viruses. The phenotype of one of the mutant HIV-2 proviruses suggested that the posttranscriptional effects may also occur. In addition to the po...