FIG. 3.
Quantification of M. tuberculosis CEQ in mouse lungs is not limited by a detection ceiling at high bacterial loads. C57BL/6 mice (A) and IFN-γ−/− mice (B) were aerosol infected with M. tuberculosis (∼4,000 CFU per mouse). At 24 h and 4 weeks (w) postinfection, mice were sacrificed and lungs were removed for analysis. Viable counts were quantified by plating serial dilutions of lung homogenates for CFU (open bars); total counts (CEQ) were quantified by QPCR (shaded bars). Bars represent mean CFU or CEQ values (n = 4 mice per group); error bars, standard deviations. This experiment was performed once.