Fig 3. Waddlia chondrophila induce severe pneumonia.

Mice were inoculated intranasally with 2 x 10⁸ W. chondrophila. Adjacent lung sections were stained with haematoxylin and eosin, anti-F4/80 antibody, and specific polyclonal anti-W. chondrophila antibody at different times post-inoculation. Scale bar = 100 μm. A) One hour post-inoculation, no signs of inflammation and no macrophage recruitment were observed. Only rare bacteria were detected within lung cells. Magnification 100x. B) Three days post-inoculation, we observed a subacute inflammation associated with a moderate recruitment of macrophages, and a massive infiltration of W. chondrophila. Magnification 100x. C) Ten days post-inoculation, we observed a moderate inflammation since the lympo-plasmacytic infiltration has slightly decrease, whereas there was still recruitment of macrophages in the rare areas where W. chondrophila was still persistent. Magnification 100x.