Figure 1: Bacilli burdens and representative histopathology in the lungs of BALB/c mice after intratracheal high dose inoculation of M. bovis mce- 2A mutant or its parental strain: (A) Mice were sacrificed at the indicated days post infection and their lungs used to determine colony forming units. Infected animals with the mutant strain showed lower bacilli loads. Asterisk represents statistical significance (p<0.05) (B) Left figure shows smaller area of pneumonia (asterisk) in a mouse infected after 60 days with the mutant strain, than the lung of mouse infected with the parental strain at the same time point (right panel). (HE staining, 200x magnification).