Figure 6.

Inhibition of ¹²⁵I-gp120 binding and HIV-1 infection by anti-CCR5 mAbs. (A) Inhibition of ¹²⁵I-labeled M-tropic HIV-1 JR-FL gp120 binding to CCR5 L1.2 transfectants by mAb 2D7 and 3A9. CCR5 L1.2 cells were incubated with 0.2 nM ¹²⁵I-labeled gp120 and 20 nM sCD4 in the absence or presence of increasing concentrations of mAb 2D7 or 3A9. After 60 min at room temperature, cells were washed and counted as described in Materials and Methods. An IgG1 control mAb was used as a control. 100% of inhibition was defined as that caused by 100 nM of unlabeled gp120. (B) Inhibition of HIV-1 infection in U87-CD4-CCR5 cells by mAb 2D7. The infectability of U87-CD4-CCR5 cells by M-tropic (ADA and JR-FL), dual-tropic (DH123), and T-tropic (HxB2) HIV-1 strains, in the absence or presence of increasing concentrations of 2D7 or 50 μg/ml of an IgG1 control mAb, was determined using a virus entry assay based on single-cycle infection as described in Materials and Methods. Infection of the cells was measured by quantification of luciferase activity.