Fig 1.

Lung lesions and bacterial burden in M. tuberculosis-infected mice. The photomicrographs show representative sections of formalin-fixed paraffin-embedded lung tissue stained with hematoxylin and eosin to determine lung pathology (A) or with Putt's stain to visualize acid-fast bacilli (B) from C57BL/6 (left), BALB/c (middle), and DBA/2 (right) mice infected with aerosolized virulent M. tuberculosis (9 weeks p.i.). (B, left) The arrows indicate examples of rod-shaped bacteria or clusters of bacteria. Magnification, ×100. (Right) CFU in the lungs 9 weeks p.i. Lung lesions and the ability to control M. tuberculosis growth were determined in two separate experiments, with 3 to 5 mice per group in each experiment. The graph shows means ± SEM from one representative experiment. *, P < 0.05; ***, P < 0.001 by one-way ANOVA with Bonferroni posttest.