Tissue myeloid cells in SIV-infected primates acquire viral DNA through phagocytosis of infected T cells

Abstract

The viral accessory protein Vpx, expressed by certain simian and human immunodeficiency viruses (SIVs and HIVs), is thought to improve viral infectivity of myeloid cells. We infected 35 Asian macaques andAfrican green monkeys with viruses that do or do not express Vpx and examined viral targeting of cellsinvivo. While lack of Vpx expression affected viral dynamics invivo, with decreased viral loads and infection of CD4+ Tcells, Vpx expression had nodetectable effect on infectivity of myeloid cells. Moreover, viral DNA was observed only within myeloid cells in tissues not massively depleted of CD4+ Tcells. Myeloid cells containing viral DNA also showed evidence of Tcell phagocytosis invivo, suggesting that their viral DNA may be attributed to phagocytosis of SIV-infected Tcells. These data suggest that myeloid cells are not a major source of SIV invivo, irrespective of Vpx expression.