FIG 8.

Vaccination with Francisella tularensis waaY or waaL mutant provides protection against challenge with F. tularensis Schu S4. Groups of 5 BALB/c mice were initially infected with three doses, from 10² to 10⁴ CFU, of F. tularensis waaY::TrgTn or F. tularensis waaL::TrgTn. At 14 days postinfection (DPI), mice were rechallenged with 5 × 10⁵ CFU of the same strain. Twenty-eight days later, F. tularensis waaY::TrgTn-infected mice were challenged intraperitoneally with F. tularensis Schu S4 (A), and F. tularensis waaL::TrgTn-infected mice were challenged intranasally with F. tularensis Schu S4 (B). Mice were tracked for 14 days for signs of disease.