a, b MDMs were infected with different amounts of HIV-1GFP with or without virion-packaged Vpx in the presence or absence of extracellular dNTP addition to match infection levels. a Infection was assessed by flow cytometry. b Supernatants from infected cells were assayed on HEK-Blue IFN-α/β cells for the presence of type I IFN. c mRNA levels for IFNB1, IFIT1 and IFIT2 were quantified by qRT-PCR and normalized to uninfected cells. d MDMs were infected with HIV-1GFP with dNTP addition, in the presence or absence of 10 µM NVP. mRNA levels for the indicated ISGs were measured by RT-qPCR, normalized to HPRT1 and then to uninfected cells. e Supernatants from the infected MDMs in d were assessed for IFN-β secretion by ELISA. N.D.: Not detected.