FIG. 2.

Fusion kinetics of HR-1 and HR-2 mutant panels. The kinetics of fusion of two panels of patient-derived HR-1 (A and C) or HR-1 and HR-2 (B and D) mutant Envs were determined by a β-lactamase cell-cell fusion assay. The results for mutant panels derived from two patients, patient 3501 (A and B) and patient 3518 (C and D), are shown. Fusion is expressed as a percentage of the maximal fusion mediated by each Env. Results are averages ± standard errors of the means for at least three independent experiments. The kinetic parameters are described in Table 1.