Productive HIV-1 infection is enriched in CD4-CD8- double negative (DN) T cells at pleural sites of dual infection with HIV and Mycobacterium tuberculosis

A higher human immunodeficiency virus 1 (HIV-1) viral load at pleural sites infected with Mycobacterium tuberculosis (MTB) than in peripheral blood has been documented. However, the cellular source of productive HIV infection in HIV-1/MTB-coinfected pleural fluid mononuclear cells (PFMCs) remains unclear. In this study, we observed significant quantities of HIV-1 p24+ lymphocytes in PFMCs, but not in peripheral blood mononuclear cells (PBMCs). HIV-1 p24+ lymphocytes were mostly enriched in DN T cells. Intracellular CD4 expression was detectable in HIV-1 p24+ DN T cells. HIV-1 p24+ DN T cells showed lower surface expression of human leukocyte antigen (HLA)-ABC and tetherin than did HIV-1 p24+ CD4 T cells. Upon in vitro infection of PFMC CD4 T cells from TB mono-infected subjects, Nef- and/or Vpu-deleted HIV mutants showed lower generation of HIV-1 p24+ DN T cells than the wild-type virus. These data indicate that productively HIV-1-infected DN T cells, generated through down-modulation of surface CD4, likely by HIV-1 Nef and Vpu, are the predominant source of HIV-1 at pleural sites of HIV/MTB coinfection.