Fig. 9

Functional characterization of the defective B 202G Env. a, b Binding efficiency of viral envelopes to CD4 and CCR5. a Binding competition assay at 37 °C of increasing amounts of purified soluble gp120 with 0.4 nM of the anti-CD4 mAb Q4120. Triangles wt B Env, squares B 202G Env. n = 3. b Equilibrium saturation binding at room temperature of wt B and B 202G gp120 to crude membranes expressing CCR5. The curves represent specific binding of gp120 determined in the presence of 200 nM of soluble CD4. Triangles wt B Env, squares B 202G Env. n = 3. c, d Viral binding to target cells and viral entry over time. c Luciferase and d p24 levels measured as function of the time of pre-incubation of the cells with the virions. Filled symbols Experiments with HEK 293T CD4⁺ CCR5⁺, empty symbols experiments with HEK 293T cells. Triangles Virions carrying wt B Env, circles virions carrying B 202G Env. Values measured for the 6 h time point with wt B Env and HEK 293T CD4⁺ CCR5⁺ were set to correspond to the maximum values in both panels. n = 3