Fig. 7. Cross-protection against WNV with one-shot low-dose immunization of JEV-ΔNS1.
a Schematic diagram of animal experiment design and schedule. b, c ELISA for the detection of antibody titers. Four-week-old female C57BL/6 mice (n = 10 for PBS- and 3 × 107 IU of JEV-ΔNS1-immunized groups; n = 5 for the other groups) were i.p. immunized once with different dosages of JEV-ΔNS1 (3 × 104, 3 × 105, 3 × 106, or 3 × 107 IU). On days 14 and 28, the sera were collected for the measurement of IgG antibody titers against JEV (b) and WNV (c), respectively. All mice were i.p. injected with 3 × 107 PFU of WT WNV at 30 days post immunization. The mortality (d) and weight loss (e) were monitored daily. The viremia (f), viral load in various organs (g), IgG post challenge titers (h) and neutralizing antibody titers (i) against WNV at the indicated times post challenge were assayed as described in “Methods”. The dashed lines in panels (b, c, f−i) represent the limits of detection. Data represent the mean ± standard deviation (SD) of five mice at each time point in each group. Statistical analysis was performed with unpaired t test and Kaplan−Meier survival curves were analyzed by the log-rank test. The asterisks denote statistical differences between the indicated groups. *p < 0.05; **p < 0.01; ****p < 0.0001; n.s. no statistical differences.