Fig. 2.

Neutralization potency of the anti-NHR antibody D5 is enhanced by FcγRI. (A) Inhibition of infection by viruses pseudotyped with Env from HXB2 (tier-1, clade B) by D5 IgG (Left) and D5 Fab (Right) in TZM-bl cells not expressing (solid) or expressing (open) FcγRI. Potentiation of >5,000-fold occurs in TZM-bl/FcγRI cells for the IgG but not the Fab form of D5. Curves plotted are from a single experiment; error bars are the range of n = 2 measurements. The table shows ID₅₀ mean values and SEM from duplicate experiments. (B) ID₅₀ values (in μg/mL) and neutralization curves of D5 IgG inhibiting infection of Env-pseudotyped lentivirus (HXB2) in TZM-bl cells stably expressing various Fcγ receptors. Each point is the mean value of a triplicate measurement; error bars are the SEM from n = 3 values. Comparable results were obtained with Env from the tier-2 HIV-1 isolate 25710 (67).