Figure 6.

Protection against Mtb challenge induced by immunization. Groups of BALB/c mice (n=10/group) immunized s.c. with BCG (WT-BCG), rBCGΔ-LTAK63, or not immunized (Control) were challenged i.n. with 500 CFU of Mtb. Thirty days after challenge, the lung was recovered to evaluate CFU (A), functional lung area, represented by the intra-alveolar space (B) and inflammatory area (C), represented by the inflammatory infiltrate of lung sections stained with H&E. Functional area and lung inflammation scores are presented as the mean percentage of inflammation for each mouse and the infiltrate is presented as cell counts per mm². **p < 0.01, ***p < 0.001 and ****p < 0.0001. Representative histopathology of lungs from naïve mice (Saline), infected only (Control), or immunized and challenged (BCG and rBCGΔ-LTAK63). Lung sections were stained with H&E (bar, 100 µm) (D). Challenge experiments were performed twice.