Fig. 5. Immunogenicity of a ZIKV M-E vaccine.

Macaques (four per group) were immunized at weeks 0 and 4 with 1, 0.3, or 0.1 mg of DNA plasmid VRC5685, and challenged with ZIKV at week 8. (A) Serum were used in neutralization assays with standard ZIKV RVPs. Dots represents the average EC₅₀ titer for each dose group; error bars indicate the standard error. Red arrows indicate administration of vaccine. (B) Viral loads were measured by qRT-PCR after challenge with ZIKV. Each dot represents the average viral load for each dose group. (C) Week 8 serum was used in pairwise neutralization assays against standard and +Furin ZIKV RVPs. Each dot represents the average of three experiments for an individual animal. Dashed lines connect EC₅₀ titers from the same animal. Bars denote the group average. Std vs +Furin EC₅₀ values per dose group were compared by a one-way ANOVA. Dotted lines represent the LOD of the assay. (D) The data from panel C is expressed as the fold difference of Std vs +Furin EC₅₀ values per dose group and shown in comparison to previously published data from animals that had received the ZIKV prM-E DNA vaccine candidate VRC5283 (12).