Figure 6. Immunization with the FTL_0325 mutant induces an early inflammatory response.

BALB/c mice were infected with 1×10⁷ CFU of the F. tularensis LVS, FTL_0325 or FTL_0304 mutant and the lungs were harvested at the indicated times, sectioned and stained with H & E. Representatives of H & E stained lung sections are shown. Infiltration of neutrophils is shown in the inset (Magnification 10×; Inset 100×). Ψ = Mice infected with 1×10⁷ CFU of F. tularensis LVS succumbed to infection by day 7 PI and hence were unavailable for comparison. Green arrows indicate the sites of cellular infiltration. Yellow circles in inset show neutrophilic infiltration in the lungs of FTL_0325 mutant immunized mice.