Figure 2.

Extended interval between antibiotic treatment and immunization prevents antibiotic-induced vaccine hyporesponse. (A) BALB/c mice were orally treated with vancomycin for 7 days (colored rectangles), followed by 1, 7, 14, or 21 days without antibiotic treatment prior to immunization with OVA and VA-510 LNPs on Days 0 and 20 (blue syringes). Harvesting of serum is indicated by red droplets. Fecal samples collected throughout the antibiotic and vaccination phases were subjected to 16s rRNA gene sequencing. The mean microbiome community dissimilarity compared to the average baseline community composition across all groups, calculated using the Bray–Curtis metric and plotted over time. Data are mean and standard error for each treatment group. (B) Serum anti-OVA IgG titers were measured at Day 34; measurements from individual mice (circles) are superimposed on group mean (bar). ** p < 0.01 compared to water by one-way ANOVA with Dunnett’s post hoc test. (C) Correlation scatter plot of each individual mouse’s OVA-specific IgG titer versus distance between the microbial community composition and the average composition of water-treated animals, measured at Day-1. Red line indicates linear regression line of best fit; gray shading represents 95% confidence interval.