Linear regression was utilized to determine the end-point titers of the antibodies against different antigens. In addition, the survival differences between animal groups were tested by log-rank test using GraphPad Prism software (San Diego, CA). End-point antibody titers in log 10 scale of different groups were compared by one-way Analysis of Variance (ANOVA). If this was significant at alpha = .05, we proceeded to look at pairwise comparisons using t-tests. For four or more groups (mice studies), the p-values from the pairwise tests were compared to a Bonferroni-adjused threshold of .05/6 = .008, where 6 comparisons were being made between each set of 4 groups with relevant immunogens. For three groups (ferret studies), we used instead Fisher's Least Significant Difference method to maintain a threshold of alpha = .05 for the pairwise tests following a significant ANOVA.