Histology of lungs infected with different lineages of <i>M. tuberculosis</i>.

<p>Sections of the lungs were stained with H&E stain. Representative lung sections for each <i>M. tuberculosis</i> infected group at day 14 and day 28 post-infection are displayed (A). Lung sections were scored (blind to the strain lineage) for lymphocytic infiltrates (B) and granulomas (C) and mean scores for each group presented. A score of 0 = normal lung; a score of 2 = moderate lymphocytic infiltrate/granuloma formation seen; a score of 3 = extensive lymphocytic infiltrate/granuloma formation seen. The displayed histology images are from one experiment only.