Figure 1.

Control of early M. bovis BCG growth in the lung is dependent on IFN-αβ receptor expression: 8–10-week-old C57BL/6 mice were infected with either (a) a low dose (595 ± 32 CFU, n = 3) or (b) a high dose (4087 ± 1103 CFU, n = 4) aerosol of M. bovis BCG using the Inhalation Exposure System (Glas-Col). At designated times, lung homogenates were prepared and CFUs were determined as previously described.³⁰ Three or four mice were analysed at each time-point and statistically significant differences are shown (*P ≤ 0·05 by Wilcoxon Rank Sum test). Data are representative of three independent experiments with low- and high-dose infections.