IFIT1 and infection: (B) Fold induction of IFIT1-Luc after activation of STING by cGAMP (5 μg/ml) and infection with HIV-1 virus-like particles (VLP) lacking genome and bearing Vpr (+Vpr) or lacking Vpr (-Vpr) (1 RT U/ml) in IFIT1-Luc reporter THP-1 cells.