Anti-ATP synthase antibodies block APC-mediated transfer of HIV-1 at the cell-cell interaction step. APC-mediated HIV-1 transfer was carried out either with DC Raji cells (A-B) or with DCs (C-D). The indicated antibodies (20 μg/mL) were added either at the step of APC–HIV-1 interaction (A,C) or added at the step of incubation of the virus-primed APCs with target TZM cells (B,D). No Ab indicates no antibody added; IgG, nonimmune mouse IgG; DC-SIGN, anti–DC-SIGN; and anti-ATPsyn, anti-ATP synthase β-chain. All antibodies were at a concentration of 1.2 × 10−7M. Transfer activity was measured by viral infectivity given in luminescence arbitrary units. A total of 100% transfer activity was determined as the maximal activity obtained in the absence of added antibody (No Ab). Experiments were carried out at least 3 times, and bar graphs represent SEM of triplicate samples.
