Inhibition of HIV-1 trans-infection by various HIV-1–specific Abs. HIV-1–specific Abs were added 2 hours after the infection of immature MoDCs at the same time as PHA-activated CD4 T lymphocytes. After 48 hours of culture, infection was determined by the detection of HIV-1 intracellular p24 Ag production by flow cytometry or by the detection of viral p24 Ag released into the supernatant by ELISA. Percentages of infected MoDCs (black squares) or CD4 T lymphocytes (gray triangles) after coculture in the presence of a panel of different anti–HIV-1–specific Abs: anti-gp120 NAbs b12 (A) and 2G12 (B); anti-gp41 NAbs 4E10 (C) and 2F5 (D); and NNAbs 246-D (E) and 4B3 (F). The percentage of viral p24 released into the supernatant of the coculture is indicated by black dots and asterisks. Dashed lines correspond to the IC₇₀ concentrations of Abs. The curve corresponds to the means ± SD of at least 4 independent experiments performed with cells from 4 different healthy blood donors.