Complement opsonization of HIV-1 inhibited antiviral responses and increased infection in DCs. DCs (1 × 106/ml) were exposed to F-HIV, C-HIV, and CI-HIV at an MOI of 8 or mock treated and evaluated for expression of IFN-β (A and B) and MxA (C and D) by lysing the cells and performing qPCR (A and C), measuring cytokine concentration in the supernatants (B), or by Western blot (D). (E) Levels of the early HIV transcript gag were determined by qPCR. (F) DCs were exposed to F-HIV or C-HIV for 3 h at 4°C, washed, and infection was assessed by measuring levels of HIV p24 release in supernatants 3, 7, and 10 d after exposure using ELISA. qPCR values have been normalized with mock values set to 1. Data are shown as means ± SEM (A–C and E) or representative results (D and F) of 3–12 independent experiments. *p < 0.05.