PXDN mutant mice reveal impairment in bacterial clearance during acute lung infection.

<p><b>(A)</b> Decrease of relative survival rates. PXDN-deficient and C57BL/6 wild-type mice were intratracheally instilled with 7 x 10⁶ of <i>P</i>. <i>aeruginosa</i> strain K or PBS control. Relative survival rates were determined over a period of 48 hours; n = 9–11 per group, <i>P</i> = 0.0068. <b>(B)</b> Lung Bacterial burden. Mice were sacrificed at 20 hours; lungs were aseptically removed, weighed, and homogenized in PBS. Lung tissue suspension was serially diluted and plated on LB agar plates. After incubation at 37°C for 18 h, CFUs were counted and CFUs/mg tissue were calculated; n = 12 from 4 mice per group; one-way analysis of variance, <i>P</i> < 0.0001 for all comparisons. <b>(C and D)</b> Tissue burden on bacterial infection with sublethal dose was carried out by intratracheally infecting the mice with 3 x 10⁶ of <i>P</i>. <i>aeruginosa</i> strain K. After 20 h, lung, liver and spleen were taken as in (B) for detection of bacteria. n = 15–21 from 5–7 mice per group; P (lung) = 0.016; P (liver) = 0.843; P (spleen) = 0.014. <b>(E)</b> H&E staining of the lungs from uninfected and infected mice. Mice were infected as in (<b>C</b>) and the lungs were harvested at 20 h for preparation of staining. a. WT mouse, uninfected; b, WT mouse, infected; c. PXDN-deficient mouse, uninfected; d, PXDN-deficient mouse, infected. Magnification: 400x. Scale: 5μm.