Fig. 3
Protective abilities of JEV-NTE- or DV/ZV-NTE-immune sera in vivo. A, B Groups of 4-week-old ICR mice were first i.p. immune with different doses of A JEV-NTE- or B DV/ZV-NTE-immune sera, while 50 μg pre-immune sera treatment was used as a control. After 1 day, all the mice were i.p. challenged with 105 PFU of JEV and i.c. injected with 30 μl PBS to break the BBB simultaneously. The numbers of animals (n) in each group are shown. The data are representative results of two independent experiments. The survival rates of the infected mice were monitored daily for 21 days. C, D Groups of 6-week-old AG129 mice were first i.p. immune with 1, 10 or 50 μg of C JEV-NTE- or D DV/ZV-NTE-immune sera, and 50 μg pre-immune sera was used as a control. After 1 day, all the mice were i.p. challenged with the indicated four serotypes of DENV and ZIKV. Serum samples were collected from the AG129 mice on day 3 post-infection. Viremia levels of each group were measured from serum samples by focus-forming assay. Each dot represents the viremia level of an individual mouse. Data are the means ± SD of two independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 [by Log-rank (Mantel-Cox) test or One-way ANOVA]. ns not significant