Effect of CCR5 mutations on entry of parental and resistant Env-pseudotyped viruses^*.

*The values recorded are the relative entry efficiencies of the CC1/85 cl.7, CC101.19 cl.7, CC1/85 cl.6 and D1/85.16 cl.23 Env-pseudotyped viruses into U87-CD4 cells transiently expressing (for 48 h) the CCR5 proteins indicated. Luciferase expression was measured 72 h after infection, and is normalized relative to the entry of each virus via WT CCR5 (defined as 100%). Each value is the mean±SEM of at least three independent determinations. A 50% decrease in entry efficiency was considered to be meaningful in this assay, so all values ≤50% are bolded. It is possible that lesser decreases (e.g., 30–50%) might also be biologically relevant.