ERVW-1 and HIV-1 infection: These results support a role of IL-1β in the induction of miR-103 and the downregulation of CCR5 during HIV-1 infection of MDMs, yet other factors secreted into the supernatant, such as IFN-α (37) (Fig. 4 and Fig. S1), RANTES, macrophage inflammatory protein 1α (MIP-1α), and MIP-1β (38), are also likely to contribute to the reduced levels of CCR5 (at both the mRNA and surface protein levels) in Supnt-exposed cells.