FIG. 9.

Neutralization and escape of HIV-1_JRFL. (A) Cell-free virus neutralization. HIV-1_JRFLluc preparations were preincubated with the indicated concentrations of Ab for 12 min at 37°C and then magnetically adsorbed to Cf2Th-CD4/CCR5 cells for 2 min. Cells were then washed, and infectivity was assayed 2 days later. Results are presented as percentages of the mean infectivity measured in the absence of Ab ± SEMs for three replicate samples. (B) Kinetics of escape of cell-bound HIV-1_JRFL from neutralization by 2 μg/ml MAb b12 and 32 μg/ml MAb 2F5. Data are presented as percentages of the mean infectivity measured in cultures not treated with Ab ± SEMs for three replicate samples. Results are representative of two independent experiments performed separately. (C) Escape of cell-bound HIV-1_JRFL from Abs in the presence of TAK-779. Cf2Th-CD4/CCR5 cells were preincubated with the indicated concentrations of TAK-779 suspended in culture medium for 30 min at 37°C and then magnetically adsorbed with HIV-1_JRFLluc. Cells were further incubated for 15 min, and the medium was removed and replaced by culture medium containing 2 μg/ml MAb b12, 32 μg/ml MAb 2F5, or no Ab. Two days later, cultures were assayed for luciferase activity. Infectivities measured in cultures treated with no Ab are presented as mean relative light unit (RLU) measurements ± SEMs for three replicate samples (▴). Bars represent ratios of the mean infectivity measured in cultures treated with MAb 2F5 to that measured in cultures treated with MAb b12.