HIV-1 replication in iDCs upregulates tetherin independently of Vpu. (A) Supernatants from DCs infected with WT HIV-1 NL(AD8) or NL(AD8)ΔVpu were assessed for p24 concentration to quantify HIV-1 release. Cell lysates from iDC (B), mDC-LPS (C), and mDC-IFNα (D) infected with HIV-1 or mock infected were detected by immunoblotting for the expression of HIV-1 Gag (p55 and p24), tetherin, and GAPDH at 2 h, 3, 5 and 7 days post-infection (dpi). M, mock infection; W, WT NL(AD8); Δ, NL(AD8)ΔVpu. (E) Flow cytometry analyses of cell surface tetherin expression in iDCs infected with WT NL(AD8), NL(AD8)ΔVpu or mock infected at 3 and 5 dpi. Similar results have been observed in at least three independent experiments using DCs from different donors.