FIG 9.

Intranasal vaccination and boosting of BALB/c mice with F. tularensis waaY::TrgTn provide significant protection against challenge with F. tularensis Schu S4. (A and B) Five groups of BALB/c mice were inoculated intranasally with 675 CFU of F. tularensis waaY::TrgTn. (B) Two groups of mice were boosted with 500 CFU of F. tularensis waaY::TrgTn 14 days after the initial infection. Twenty-eight days later, the boosted and unboosted mice were challenged intranasally with F. tularensis Schu S4, and the mice were tracked for 14 days for signs of disease. A group of naive mice were infected with 19 CFU of F. tularensis Schu S4 as an infection control.