FIG 2.

IC₅₀ titers of monoclonal antibodies against the wild-type and mutant clones. Monoclonal antibodies targeting the variable loop 2 (V2), V3, and CD4bs regions of Env were tested in duplicate against the viral clones in a TZM-bl neutralization assay. IC₅₀ titers were calculated with nonlinear regression by using PRISM5 and are expressed as the lowest concentration of antibody that causes a 50% reduction in RLU compared with the virus control. A titer of 50 μg/ml is plotted for data points where an IC₅₀ was not reached at the highest MAb concentration tested.