Figure 2.

Transfer of ZIKV-immune mouse sera increases the survival of ZIKV-infected mice but decreases that of JEV-infected mice. (A and B) Mouse serum samples were prepared from ZIKV-naive (mock-immune, n = 6) and ZIKV-immune (n = 6) mice. ZIKV-EDIII– and JEV-EDIII–reactive IgG levels were measured by indirect ELISA. Mouse anti-His mAb was used as positive control. Data are presented as the mean ± SEM. (C–F) 1-d-old naive C57BL/6 mice were injected s.c. with 0.05 µl (C and D) or 10 µl (E and F) of mock-immune (n = 19, n = 7, respectively) or ZIKV-immune (n = 16, n = 7, respectively) mouse sera, and 6 h later, the mice were injected s.c. with JEV (12 PFU). Mouse weights and survival were recorded daily for 14 d. Data are presented as the mean ± SD and are pooled from two experiments, each with 3–10 mice per group. (G–J) 1-d-old naive C57BL/6 mice were injected s.c. with 0.05 µl (G and H) or 10 µl (I and J) of serum from mock-immune (n = 12, n = 13, respectively) or ZIKV-immune (n = 13, n = 12, respectively) mice, and injected s.c. with ZIKV (10² FFU) 6 h later. Weights and survival were recorded daily for 28 d. Data are presented as the mean ± SD and are pooled from two experiments, each with six or seven mice/group. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 by two-tailed Mann–Whitney U test (B, C, E, G, and I) or log-rank test (D, F, H, and J).