Figure 1.

DC-SIGN transmission of HIV-1 requires donor and target cell contact Pseudotyped HIV-Luc/ADA (1 × 10⁵ IU) was preincubated with Raji or Raji/DC-SIGN donor cells (2.5 × 10⁵) for 2 h at 37°C; the cells were washed with 1 ml of PBS and then cocultured with Hut/CCR5 target cells (1 × 10⁵) in the presence of 10 μg of polybrene in 1 ml of culture medium. Transwell cell culture plates with polycarbonate membrane inserts (3 μm pore size) were used in the capture and transmission assays to separate HIV-1-pulsed donor cells from target cells as illustrated. Cell lysates were obtained 2 days after infection and analyzed for luciferase activity. Each data set represents the mean of three separate wells of infected cells. One representative experiment out of three is shown. cps, counts per second.