TNF expression in the lungs of mice infected i.n. with <i>F. tularensis</i> LVS.

<p>(A) Groups of 3–4 mice from the indicated strains were infected intranasally with 6,000 CFU of LVS. At day 5 post-infection, BALF was recovered from each mouse and cytokine levels quantified by BD™ Cytometric Bead Array (BD Biosciences, San Diego, CA). The data are expressed as the average cytokine level (+ SEM) from 3–4 individual mice. Significant differences among groups were determined by Kruskal-Wallis ANOVA on ranks followed by Dunn's post-hoc analysis; ^*<i>p</i><0.05. (B) Groups of 2–3 B6, MyD88^−/− and TLR2^−/− mice were infected i.n. with 3,600 CFU of LVS or mock-infected and sacrificed after 1, 3, and 5 days post-infection. Lung tissue cryosections were prepared at the indicated time points and stained with purified goat anti-TNF (red) followed by Rhodamine Red-X-conjugated anti-goat Ig and analyzed by <i>in situ</i> immunofluorescence microscopy. Nuclei of cells (blue) were visualized via staining with 4′6′diamidino-2-phenylindole-dilactate (DAPI). The same sections were also stained for bacteria (green) with Alexa488-conjugated mouse anti-LVS LPS. Representative images from 2–3 mice are shown. Magnification for all images is 400×.