FIG. 4.

Comparison of the HIV-1 neutralization potency of sCD4-17b with those of anti-Env MAbs. Virus samples were preincubated with increasing volumes of concentrated media from cells infected with vCD-3 (containing sCD4-17b at the indicated concentrations) or WR (control), or with increasing amounts of purified MAb IgGb12, 2G12, or 2F5. Infectivity was assayed with MAGI-CCR5 cells. Results are expressed as the percentage of blue cells compared to the level (taken as 100%) in a parallel control in which virus was preincubated with no additional proteins (which gave 770 blue cells per well). Error bars indicate standard deviations of duplicate samples.