FIG. 1.

Inhibition of variable loop-deleted gp120 glycoprotein binding to CCR5 by CD4BS antibodies. Radiolabeled ΔV1/V2 gp120 glycoproteins from the ADA strain (A) or JR-FL strain (B) of HIV-1 were incubated at 37°C with Cf2Th cells expressing CCR5 in the presence of the indicated amounts of CD4BS antibodies (F105, IgG1b12, and 15e) or a control antibody, C11. The amount of the ΔV1/V2 gp120 glycoproteins bound to the Cf2Th-CCR5 cells is presented as the percentage of the amount bound in the absence of antibody. The experiment was performed twice with comparable results.