Fig. 2
In vivo immunogenicity of YF-ZIKprM/E and protection of AG129 mice against lethal challenge with ZIKV MR766. a Seroconversion of vaccinated mice: AG129 mice (n = 15) were inoculated with 1 × 104 PFU of YF-ZIKprM/E and the titers of ZIKV-specific neutralizing antibodies were assessed in serum at 21 days post immunization by PRNT (blue squares). Data compiled from three independent experiments with n = 5 per group. Sera from sham-vaccinated (n = 10) as controls (red circles). b ZIKV MR766 challenge: Twenty-one days post vaccination, vaccinated (blue squares, n = 5) and sham-vaccinated (red circles, n = 5) mice were challenged with 1 × 104 PFU of ZIKV MR766. Vaccinated mice were monitored for 28 days, and remained healthy until the end of the experiment. Protection from ZIKV viremia c and virus dissemination to target organs d, e after challenge of vaccinated (blue squares, n = 10) and sham-vaccinated (red circles, n = 10) AG129 mice. Blood and organs were collected at day 5 d and 14 e post challenge. The subset of mice represented in c–e were not included in the survival analysis b because animals needed to be sacrificed earlier for organ collection. However, at euthanasia day 14 post challenge all sham-vaccinated mice showed signs of severe ZIKV-induced disease, as well as that particular YF-ZIKprM/E vaccinated animal that failed to seroconvert prior to challenge a resulting in viral break-through (outliers in c and e). Data are presented as mean values with error bars indicating SEM from two independent experiments (n = 5 each). Mann–Whitney two-tailed test was used for all statistical calculations. P values < 0.05 were considered statistically significant. *P < 0.05, **P < 0.01, ***P < 0.001. Horizontal dotted lines denote the limit of detection (L.O.D) of the assay
