Figure 5.
Histopathology of the lungs of mice challenged with a lethal dose of L. pneumophila. Each group of mice (n = 3/group) was immunized s.c. with P8 plus CpG-ODN at 0, 1, and 2 weeks. At 3 weeks, the mice were treated i.p. with 150 mg/kg of cyclophosphamide every day for 3 days. Next day, the mice were challenged i.n. with 1 × 109 CFU of L. pneumophila. Upon animal death after the challenge, the lungs were removed from the mice and the lung tissues were sectioned, followed by staining with hematoxylin-eosin. Cell nuclei were stained dark blue, and cytoplasm were pink. Representative images of inflammatory lesions are shown (magnification, × 200).