Figure 1

Vpu-dependent BST-2/tetherin cell surface down-regulation but lack of BST-2/tetherin restriction activity in DC. (A). 2 × 10⁵ DC (A, upper panel) and Vpx-transduced DC (A, lower panel) were infected or not (NI) with HIV-WT or HIV-ΔVpu viruses. Infection of DC was scored by FACS analysis of BST-2/tetherin⁺/p24gag⁺ cells, three days post-infection. Percentage of cell surface BST-2/tetherin⁺ in infected DC from 7 independent experiments was calculated (right graph panels). (B) TZM-bl cells were incubated for 48 hours with 1/10 volume of supernatant from HIV-WT or HIV-ΔVpu infected DC or myDC harvested three days post-infection. Infectious units (IU/ml) were quantified using the β-gal assay obtained from 5 and 3 experiments in DC and myDC respectively. (C) Similar experiments (as above) were performed with supernatant obtained from HIV-WT or HIV-ΔVpu infected Hela cells (results from duplicate experiments). Error bars represent the mean ± SD of indicated experiment numbers. (D) Lysates and supernatants of uninfected (NI), HIV-WT or HIV-ΔVpu infected DC were subjected to immunoblotting with anti-Gag and anti-BST-2. The presence of Vpu was assessed by immunoblotting with anti-Vpu and anti-actin served as loading control.