(A) Luciferase reporter viruses pseudotyped with R3A or TA1 were incubated with various concentrations of the MAb CTC5 for 1 h prior to infection of 293.CD4.CCR5 cells. The amount of luciferase activity obtained for each virus pseudotype in the absence of any antibody was set to 100%. The results shown are the average for three independent experiments, ± standard error of the mean.
(B) Luciferase reporter viruses pseudotyped with R3A (white bars) or TA1 (black bars) Env were incubated with 293T cells expressing CD4 only, CD4 and CCR5, or CD4 and mutant CCR5, as indicated. Δ2–17 refers to a CCR5 construct lacking amino acids 2–17. Single amino acid mutants refer to changes in the CCR5 N-terminus. The amount of luciferase activity obtained for each virus pseudotype on WT CCR5 was set to 100%. The results shown are the average for three independent experiments, ± standard error of the mean.