Figure 7From: The role of the N-terminal segment of CCR5 in HIV-1 Env-mediated membrane fusion and the mechanism of virus adaptation to CCR5 lacking this segmentRescue of the CCR5(Δ18) coreceptor function by the S22 peptide. (A) Cells expressing Env(wt) (open circles) or Env(NYP) (filled circles) were co-cultured with HeLa-CD4 cells expressing a relatively high density of CCR5(Δ18) (the R5d18.23 line) for 3 hr at 37°C in the presence or in absence of S22. For comparison, cell-cell fusion induced by JRFL Env in the presence of varied concentrations of the S22 peptide is shown by open triangles. (B) Fusion between Env(NYP)- (filled bars) or Env(wt)-expressing (open bars) cells and CD4/CCR5(Δ18) cells after establishing a 27°-TAS. Two μM of C52L was added (first column) or not added (second column) after creating TAS (27°C, 2 hr) prior to warming cells to 37°C and incubating for additional 2 hr. Third column shows fusion observed when 200 μM S22 was present during the last 30 min of a 2 hr pre-incubation at 27°C required to create TAS. Alternatively, a 27°-TAS was created in the presence of 200 μM S22 peptide, and cells were additionally incubated for 2 hr at 37°C (fourth column).Back to article page