FIG 6.

Antisera from mice vaccinated with gpE1/gpE2 compete for binding of HCV cross-neutralizing MAbs to gpE1/gpE2. Competition studies were done by using mouse antisera against a panel of cross-neutralizing monoclonal HCV antibodies. Microtiter wells coated with purified H77C gpE1/gpE2 were incubated with diluted postvaccination antiserum (1:100) in triplicate for 1 h at 37°C, followed by incubation with the indicated MAb for another hour at 37°C. The binding of the MAbs was detected with anti-human alkaline phosphatase-conjugated secondary antibodies (see Materials and Methods). For mouse MAb H77.16, the antibody was first conjugated with biotin and then detected with a streptavidin-conjugated secondary antibody. Percentages of MAb binding were calculated relative to the amount of MAb bound in the absence of mouse antiserum. Shown are mean values for each group ± ranges from two independent experiments. Vaccinated mouse groups (control [C] or vaccinated with gpE1/gpE2 [WT] or HVR1-deleted gpE1/gpE2 [ΔHVR1]); E2-specific antibodies H77.16, HC33.4, HC84.26, and AR3b; and gpE1/gpE2-specific antibodies AR4a and AR5a were used (Table 1). Statistical analysis was done by one-way analysis of variance with a Tukey post hoc test (GraphPad); only statistically significant difference are highlighted. *, P < 0.05. Nonsignificant differences are not labeled.