Figure 6. Infection of immunocompetent C57Bl/6 mice with M. tuberculosis kasB isogenic strains. (A) Growth of Mtb kasB strains in the lungs.

Low-dose aerosol infection was performed with the following Mtb strains: parental, KasB_T334A/T336A, KasB_T334D/T336D, and ΔkasB. Lungs from infected mice were harvested at 1, 7, 21 and 57 days post-infection, homogenized and serial dilutions were plated onto Middlebrook 7H10 plates supplemented with 10% OADC and 0.2% glycerol. (B) Pathology slides of lungs from infected mice at 21 days post-infection. Lung tissue sections from mice infected with the Mtb CDC1551 parental, KasB_T334A/T336A, KasB_T334D/T336D, and ΔkasB were stained with hematoxylin/eosin and observed. Magnification = ×20. (C) CFU plots in the liver and spleen three weeks (black bars) and eight weeks (grey bars) post-infection.