FIG. 6.

Sensitivities of β-galactosidase reporter HIV strains pseudotyped with the sCD4 and NBD-556 resistance envelope mutations to CD4i MAb 4C11 with or without NBD-556. The sensitivities of β-galactosidase reporter HIV strains pseudotyped with the sCD4 and NBD-556 resistance envelope mutations to CD4i MAb 4C11 in the absence (A) or presence (B) of NBD-556 are shown. 4C11 at various concentrations and a pseudovirus suspension corresponding to 100 TCID₅₀ were preincubated with or without NBD-556 (1 μM) for 15 min on ice and then added to the target cells (TZM-bl). The inhibitory effects were determined by measuring the β-galactosidase activities on day 2 of culture. All assays were conducted in triplicate, and the data shown represent the means ± the SD derived from the results of two to three independent experiments.