Figure 7.

The ability of guinea pig sera to compete with E2- specific mAb for binding to monomeric RBD. Half-log serial dilutions of sera and constant concentrations of HCV1 (100 ng/ml) (A), AR3C (50 ng/ml) (B), HC84.27 (250 ng/ml) (C), 2A12 (250 ng/ml) (D), and CBH4G (100 ng/ml) (E) were incubated with plate-bound RBD in a competitive ELISA. mAb binding was detected using a horseradish peroxidase–conjugated secondary antibody specific for human antibody. Curves were fitted by nonlinear regression, and ID₅₀ values were interpolated using binding in the absence of guinea pig sera as 100% binding. Data are shown as the log₁₀ ID₅₀ of guinea pig sera. The dashed line shows the lower detection limit of the assay (1:10 dilution).