Figure 4

Inhibition of cell-cell fusion by the C34 peptide. The extent of fusion between Env(wt)-expressing (open squares) or Env(NYP)-expressing (open triangles) cells and CD4/CCR5(wt) cells was measured following a 2 hr-incubation at 37°C in presence of indicated concentrations of C34. When CCR5(Δ18)-expressing cells were used as targets, the C34 was added either at the beginning of co-culture with Env(NYP)-expressing cells (2 hr at 37°C, open circles) or after capturing cells at TAS (pre-incubation at 27°C for 2 hr, filled circles). When added at TAS, the C34 was allowed to bind for 5 min before warming the cells to 37°C.