FIG. 3.

Pulmonary inflammatory cellular infiltration in neonatal IFN-γ^−/−, IFN-γR^−/−, and IL-12p35^−/− mice following i.n. C. muridarum challenge. (A) Groups (n = 3–4) of 1-day-old BALB/c (a–c); IFN-γ^−/− (d–f); or C57BL/6 (g–i); or IFN-γR^−/− (j–l); or IL-12p35^−/− (m–o) mice were challenged i.n. with 100 IFU of C. muridarum. The mice were euthanized on the indicated days after challenge. The lungs were removed, embedded in paraffin, and serial horizontal sections prepared and stained with H&E. Total magnification 25× (b—bronchiole). The lungs were further scored quantitatively for pulmonary pathology. (B) IFN-γ^−/− and wild-type (WT); (C) IFN-γR^−/−, IL-12p35^−/−, and WT control mice. Results are expressed as the score of individual mice and the mean ± SD of the scores in each group. Results are representative of 2 independent experiments. *P ≤ 0.05 between C. muridarum-challenged BALB/c and IFN-γ^−/− mice, C57BL/6 and IFN-γR^−/−, or C57BL/6 and IL-12p35^−/− mice.