Figure 7. The T4 nanoparticle displayed plague immunogens induced robust immunogenicity and protective efficacy against pneumonic plague.

The immunogenicity and protective efficacy of T4 displayed plague immunogens were evaluated in a mouse model using the same immunization scheme shown in Figure 6B. (A) The T4 displayed plague immunogen groups, twelve mice per group. The Soc-fused plague immunogens were displayed on T4 phage particles and were directly used for vaccination without any adjuvant. (B) Antigen-specific antibody (IgG) titers as determined by ELISA. (C) Survival of vaccinated mice against intranasal challenge with 90 LD₅₀ of Y. pestis CO92. The survived mice were re-challenged with 9,800 LD₅₀ at day-48 post-first challenge. The animal mortality data was analyzed by Kaplan Meier's survival estimates and a p value of ≤0.05 was considered significant.