Zika virus-like particle vaccine fusion loop mutation increases production yield but fails to protect AG129 mice against Zika virus challenge
Fig 6
Immunization with lead, but not F108A VLP, significantly reduces RNAemia, which inversely correlates with nAb responses.
Animals were challenged with 5,000 FFU of ZIKV strain (Nica 2–16) SC at Day 52 as depicted in Fig 3A. (A) Viral load in serum was measured on day 2 post-challenge by RT-qPCR. Each symbol represents the log10 GE/mL for an individual mouse, horizontal bars and values above each group show group means, significance values compared to the Alum-only group are just above group mean values, and the bars and significance levels on top were obtained by comparing lead and F108A groups. The dotted line is the limit of detection (LOD) of the assay set based on the lowest log GE/mL detected (0.59 GE/mL), and the symbol † denotes a mouse with a lethal infection. Measurements below the LOD were assigned a value of half the LOD. Statistical comparisons were performed using Kruskal-Wallis test followed by Dunn’s multiple comparisons tests (ns, not significant; *P<0.05; **P<0.01; ***P<0.001; ****P<0.0001). (B) Combined lead and combined F108A VLP groups were compared to the Alum-only group. Individual viral load values, assay LOD, and the symbol † designation are as in (A). (C) The relationships between NT50 and viral load (both log10 transformed) for the combined lead VLP groups and the combined F108A VLP groups were assessed by Spearman correlation analysis with resulting r and P values shown.