FIG 4.

Neutralization of Env variants bearing eCD4-Ig-selected substitutions. HIV-1 pseudotyped with Env of the SHIV-SF162P3 sequence or the same Env modified to include the indicated eCD4-Ig-selected substitutions was used to infect TZM-bl cells in the presence of the indicated concentrations of CD4-Ig or eCD4-Ig. Luciferase activity, normalized to that for each variant in the absence of inhibitor, is shown. Error bars represent SEM. The experiment is representative of two or three with similar results. Note that only variants bearing a substitution at Q428 were more resistant to these inhibitors.