CD16⁺ monocytes exposed to HIV promote highly efficient viral replication upon differentiation into macrophages and interaction with T cells

The CD16⁺ subset of monocytes is dramatically expanded in peripheral blood during progression to AIDS, but its contribution to HIV pathogenesis is unknown. Here, we demonstrate that CD16⁺ but not CD16^- monocytes promote high levels of HIV replication upon differentiation into macrophages and interaction with T cells. Conjugates formed between CD16⁺ monocyte-derived macrophages and T cells are major sites of viral replication. Furthermore, similar monocyte-T cell conjugates detected in peripheral blood of HIV-infected patients harbor HIV DNA. Thus, expansion of CD16⁺ monocytes during HIV infection and their subsequent recruitment into tissues such as lymph nodes, brain, and intestine may contribute to HIV dissemination and establishment of productive infection in T cells.