Pathohistological Analysis of P. aeruginosa Infection 
To further evaluate the change in virulence between the parental TB isolate and the TB0173s cheB2 mutant, mice were sacrificed 2 days after bacterial challenge and the lungs were formalin fixed and paraffin embedded.
Lungs from infected mice challenged with the TB strain as well as the complemented TB0173sp2B2 strain had a pronounced polymorphonuclear neutrophil (PMN) infiltration as well as strong peribronchiolar and perivascular inflammation (Figure 5A).
In contrast, the TB0173s cheB2 mutant had caused markedly reduced inflammation and very little PMN infiltration (Figure 5B).
