Figure 4.

Lung burden of live mycoplasma after infection. Mycoplasma colony-forming units (CFUs) were measured in lung homogenates from Ctsl^+/+ (+/+) and Ctsl^−/− (−/−) mice before infection and 3, 7, and 14 days after intranasal inoculation with live M. pulmonis or medium alone (sham). Bacterial burden is expressed as total CFUs in lung homogenates. Data represent means ± SEMs (n = 3). **P < 0.01 and ***P < 0.001, versus CFUs in infected Ctsl^+/+ mice, according to t tests. No CFUs were detected in lungs of uninfected/sham-infected mice.