Figure 5.

Kinetics of neutralizing antibody-induced gp120 shedding. (A) Shedding kinetics were determined over a 33-h time period. JR-FL pseudovirus was treated with fixed concentrations of CD4-IgG2 (10 µg/ml), b12 (10 µg/ml), 2G12 (100 µg/ml), 2F5 (100 µg/ml), and 4E10 (100 µg/ml) or left untreated (medium control) for the indicated time periods at 37°C, and gp120 shedding was assessed as described in Fig. 3 B. The rate of gp120 loss was fitted according to the formula L + (100 − L) × exp(−d × time). L denotes the maximal level of gp120 loss (lowest level of gp120) inflicted by the respective antibody. The rate of gp120 loss is characterized by a constant d (units per hour). T1/2 max denotes the time until half maximal gp120 loss was reached. An overlay of five independent experiments is depicted. (B) The dose dependency of the shedding process was assessed by treating JR-FL pseudovirus with increasing concentrations of b12, 2F5, and 4E10 or by leaving the pseudovirus untreated (medium control) for 22 h at 37°C. Shedding was analyzed as described in Fig. 3 B. Data are expressed in relation to the medium control. Pooled data from three independent experiments are depicted. Curves depict sigmoid dose–dependent fits with variable slope and constraining upper limits at 100%. The dotted curves indicate the respective 95% confidence intervals.