Figure 11. The mutated and T4 displayed plague antigens provided complete protection against Y. pestis CO92 in a Brown Norway rat model of pneumonic plague.
(A) Vaccine formulations used in various groups, twelve rats per group. The rats were immunized as per the basic scheme shown in Figure 6. The soluble antigens (groups 2–4) were adjuvanted with alhydrogel. The T4 displayed groups contained no adjuvant. (B) Survival of vaccinated rats against intranasal challenge with 5,000 LD50 of Y. pestis CO92. The animal mortality data was analyzed by Kaplan Meier's survival estimates and a p value of ≤0.05 was considered significant.