Fig. 3

IL-33 deficiency transiently attenuated egg-induced pathology in the intestines of infected mice. Female IL-33^−/− and WT BALB/c mice were subcutaneously infected with 50 and 35 S. mansoni cercariae for 9 and 12 weeks, respectively, and sacrificed at 6, 9 and 12 wpi. Terminal ileum fragment was obtained from each infected and non-infected mouse (3 animals per group), fixed in 10% neutral buffered formalin, and processed for histology. a Representative hematoxylin and eosin-stained histological sections of terminal ileum from infected and non-infected WT (upper panels) and IL-33^−/− (lower panels) mice. Scale bar: 200 µm for controls, 60 µm for 6 wpi 100 µm for 9- and 12 wpi. Arrows indicate eosinophils in the inflammatory inflitrate. b Intestinal wall thickness (mucosal layer excluded) in microns. Unpaired two-tailed t-test with Welch’s correction was used to compare mouse genotypes in controls and infected mouse groups at 6 and 9 wpi, and the Mann–Whitney test was used to compare infected mouse groups at 12 wpi. c Number of granulomas per tissue section. d Granuloma area (mm²). Data are presented as the mean with SEM. Significance (P value) is indicated above connector bars between appropriate groups. The level of significance was set at P  < 0.05