Transmission and replication of HIV-1 is restricted in mDC-IFNα. Transmission of HIV-1 by DCs was assessed by incubating DCs with either the single-cycle luciferase reporter HIV-1 or replication-competent HIV-1 NL(AD8) for 2 h, then co-cultured with Hut/CCR5 target cells for 3 or 2 days, respectively; transmission was assessed by whole-cell luciferase assay or release of p24 in supernatants. (A) mDC-IFNα do not enhance transmission of the single-cycle luciferase reporter virus to CD4+ T cells over iDC transmission levels. cps, counts per second. Mock, mock infected iDCs. Data represent mean ± SEM of three independent experiments performed on DCs from three different donors. U.D., undetectable (lower than detection limit). (B) mDC-IFNα do not enhance transmission of HIV-1 NL(AD8) to CD4+ T cells at 2 dpi (days post-infection) relative to iDC transmission levels. Graph represents mean data ± SEM from three independent experiments performed with DCs from three different donors. DCs were infected with WT NL(AD8) and p24 production in the cell lysates (C) or supernatants (D) was monitored after 2 h or 3-7 dpi using a p24 ELISA. AZT was used to assess productive HIV-1 infection. Data are from one experiment and representative of at least two independent experiments.