Kinetics of Mtb growth in IFN-γ-deficient mice.

<p>BAL cells were harvested from WT and GKO mice 7, 11, 14, 18 and 21 days after aerosol challenge with 100 CFU Mtb Erdman delivered to the lung. Total cells from both sources were counted and cytospin preparations were made for Ziehl-Neelsen staining. (A) The total number of Mtb-infected (AFB⁺) cells was derived by multiplying the % AFB⁺ cells by the total number of cells in each sample. Results for individual mice are presented as log₁₀ total AFB⁺ cells, with the line representing the mean. (B) The proportion of Mtb-infected phagocytes within the total sample was counted at each time point and expressed as % AFB⁺ cells with the bar indicating the mean. Data were analyzed as detailed in <i>Materials and Methods</i>. The number of AFB⁺ BAL cells from GKO mice was significantly different (p<0.05) from WT on days 14, 18 and 21 p.i. The % AFB⁺ BAL cells from GKO mice were significantly different from WT on day 21 p.i. Data are representative from one experiment with five mice per group. In vivo experiments were repeated twice.