FIG 3.

Infectivities of the ΔclpX, ΔclpP, and Δlon mutants in BALB/c mice. BALB/c mice (n = 6) were infected with F. tularensis LVS (WT) or its derivatives via intranasal inoculation. Bacterial burdens of the lon (A), clpP (B), and clpX (C) mutants in the lung were determined at days 0, 2, 4, and 7 postinoculation. Each bar represents the mean log CFU ± SEM. All of the mouse infection experiments were repeated at least twice. The relative difference with each pair of LVS and isogenic mutant is indicated by fold change and a P value (*, <0.05; **, <0.01; ***, <0.001).