Figure 2.

Inactivated Francisella tularensis (iFt)-Mueller Hinton Broth (MHB) provides superior protection compared to iFt-Brain-Heart Infusion (BHI) against lethal Ft LVS challenge. Mice were immunized twice on days 0 and 21 with phosphate-buffered saline or iFt-MHB or iFt-BHI at a dose of 37.5 ng (A), 75 ng (B), 150 ng (C,E), or 300 ng (D). (A–D) Mice were infected 2 weeks after booster immunization with 2× LD₅₀ of Ft LVS grown in MHB. (E) Mice were infected with 2× LD₅₀ of Ft LVS grown in BHI. This figure represents Kaplan–Meier survival curves of three independent experiments with a total of 20 mice per group (A–D) or 1 experiment with 12 mice per group (E). *p < 0.05.