<i>C. pneumoniae</i> infected B6.C3H-<i>sst1</i> mice show evidence of increased apoptosis in lung tissue.

<p>C57BL/6 (B6) or B6.C3H-<i>sst1</i> congenic mice were infected with <i>C. pneumoniae</i>, and at day 3 and day 6 post infection, lungs were removed for processing, as described in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003569#ppat-1003569-g001" target="_blank">Figure 1</a>. Immunohistochemistry was carried out using monoclonal Ab against cleaved caspase-3. Panels A–B, day 3; E–F, day 6. Panels C–D and G–H are taken from the rectangle area in panels A–B, E–F, respectively. Original magnification: A–B, E–F: 100×; C–D, G–H: 400×. No caspase-3 staining in the lung was observed by immunohistochemistry in mock infected mice (data not shown).