2.9. Mouse Infection

The 90 C57BL/6 mice (45 female and 45 male) were divided into 3 groups of 30 each for the respective infection with Ms_YrbE3A, Ms_Vec, or PBST (PBS with 0.05% Tween 80). Briefly, the bacilli suspended in PBST were intratracheally delivered to corresponding groups of animals at 2 × 10⁶ CFU per mouse in 25 µL PBST, while the same amount of PBST was administered into the control mice. On days 0, 2, 4, 8, 16, and 21 postinfection (PI), 5 mice at each timepoint were euthanized, and the lungs were collected for examination of histopathology, bacterial load, and inflammatory cytokines.