Most HIV-1 transmissions occur at mucosae and involve exposure to semen. Semen contains immunomodulatory factors, which inhibit anti-HIV-1 natural killer cell and T cell responses. We demonstrate high concentrations (1:2 dilution) of seminal plasma (SP) inhibit monocyte phagocytosis and anti-HIV-1 Fc-dependent functions of both neutrophils and monocytes. In addition, slightly lower SP concentrations (1:2-1:10 dilutions) inhibit granulocyte phagocytosis and oxidative burst of both monocytes and granulocytes. These observations may have implications for HIV-1 infectivity after mucosal exposure.
Keywords: Fc receptors; HIV-1; antibodies; granulocytes; monocytes; semen.