Fig 2: IL-33 protects from mortality and epithelial barrier disruption during C. difficile infection. C57BL6 mice (a–f) or ST2−/− mice (f–i) were treated with an antibiotic cocktail prior to infection with R20291 and treated by IP injection with recombinant IL-33 (rIL-33) or vehicle control (PBS) for 5 days prior to infection. a Survival curves (b), weight loss (c), and clinical scores after infection and treatment. (d, e) Infected cecal tissue was examined with IL-33 treatment and without (day 3). d Representative epithelial damage (H&E) of treatment groups assessed by (e) blinded scoring of infected tissue (H&E). f Peak C. difficile bacterial burden in cecal contents after infection (day 2) of IL-33-treated mice or ST2−/− mice compared with the vehicle or wild-type controls. g–i ST2−/− on C57BL6 background and C57BL6 controls were cohoused for 3 weeks prior to R20291 infection. g Survival curves (h) weight loss and (i) clinical scores were assessed. a, g Comparison made by log rank test (a, n = 35, 37; g, n = 21, 20). b–e, h–i Comparison made by Student's t test (b, n = 39; c, n = 29, 30; e, n = 10; h, n = 27, 26; i, n = 20). f Comparisons for C. difficile burden were made by Mann–Whitney U tests (f, n = 11, 12, 8, 7). a–c, g–i The data combined from three independent experiments. d–f The data representative of three independent experiments. Statistical significance is demarked as *P < 0.05, **P < 0.01, and ***P < 0.001. Scale bar is 50 μm. Error bar indicates SEM

Fig 3: IL-33 protects from amebic infection and epithelial tissue damage in mice.a–d CBA/J mice were injected intraperitoneally with 0.75 µg of IL-33 or PBS each day for 8 days. On day 4 mice were challenged with E. histolytica trophozoites. Cecal content and cecal tissue were harvested on day 9 (day 5 post E. histolytica challenge). a Infection rate measured by amebic culture from cecal content. b E. histolytica DNA, measured by qPCR. c Weight loss. d Epithelial damage scored by H&E staining of cecal tissue. e–h Impact of soluble ST2: C57BL/6J mice were intraperitoneally injected 5 ug/mouse soluble ST2 (IL-33 receptor). e infection rate by amebic culture from cecal content. f E. histolytica DNA by qPCR. g Weight loss. h Correlation of amebic DNA load and ST2 concentration in cecal tissue (blue dots represent mice in soluble ST2 group and black dots represent control group). a Data pooled from two independent experiments (n = 9–10). b–d Data representative of two independent experiments (n = 9–10). e–h Data pooled from two independent experiments (n = 5–10). Statistical significance was determined by Fisher’s exact test and unpaired t test. Error bars indicate SEM.

Fig 4: IL-33-ILC2 crosstalk is protective during C. difficile infection. a–c Rag2−/− and Rag2−/−γc−/− were infected with R20291 and treated with or without IL-33. a Survival curves, (b) Rag2−/− weight loss, and (c) Rag2−/−γc−/− weight loss after IL-33 treatment and infection. d, e Immune cell profiling of ILCs within the colon of IL-33-treated or untreated mice during R20291 infection. ILCs were subsetted into ILC2s (Lin- CD45+ CD90+ CD127+ GATA+ ST2+); ILC1s (Lin- CD45+ CD90+ CD127+Tbet+), and ILC3s (Lin- CD45+ CD90+ CD127+RORyT+) by flow cytometry. d Representative dot plots of ILC subsets within the colon of PBS controls or IL-33-treated mice during infection (day 2). e Enumeration of the number of ILC2s in the colon of IL-33-treated C57BL6 or Rag2−/− mice during R20291 infection. f, g Adoptive transfer of ex vivo expanded and sorted purified ILC2s from uninfected IL-33 treated mice into naive Rag2−/−γc−/− mice. f Survival curves and (g) weight loss after ILC2 transfer and R20291 infection. h Pearson correlation between the frequency of ILC2s and the percent weight loss during R20291 infection. a, f Comparison made by log rank test (a, n = 6, 7, 10, 10; f, n = 11, 10). (b, c, e, g) Comparison made by two-tailed Student's t test (b, n = 8; c, n = 17,15; e, n = 10, 10, 4, 4; g, n = 10). h Comparison made by Spearman correlation (h, n = 39). a–c The data representative of two independent experiments. d–h The data representative of three independent experiments. Statistical significance is demarked as *P < 0.05, **P < 0.01, and ***P < 0.001. Error bar indicates SEM

Fig 5: Associations between plasma soluble ST2 levels and Alzheimer’s disease in the Chinese_cohort_1, stratified by sex and APOE-e4 genotypes.(a) Individual plasma soluble ST2 (sST2) levels stratified by sex and disease phenotype (male: n = 132 healthy controls [HCs], n = 84 individuals with Alzheimer’s disease [AD]; female: n = 204 HCs, n = 193 individuals with AD). Test for effects of sex: ß = -3.848 and -3.257 in HCs and individuals with AD, respectively; test for effects of AD: ß = 1.926 and 2.235 in males and females, respectively. (b, c) Individual plasma sST2 levels stratified by APOE-e4 genotypes and disease phenotype in (b) males (male e4: n = 28 HCs, n = 29 individuals with AD; male non-e4: n = 104 HCs, n = 55 individuals with AD), and (c) females (female e4: n = 25 HCs, n = 71 individuals with AD; female non-e4: n = 179 HCs, n = 122 individuals with AD). Test for effects of APOE-e4: ß = -1.809, -1.499, -0.248, and 2.425 in male HCs, male individuals with AD, female HCs, and female individuals with AD, respectively; test for effects of AD: ß = 2.034, 1.098, 3.833, and 1.811 in male e4, male non-e4, female e4, and female non-e4, respectively. e4, APOE-e4 carriers; non-e4, APOE-e4 noncarriers. Data are presented as box-and-whisker plots including maximum, 75th percentile, median, 25th percentile, and minimum values; plus signs (+) denote corresponding mean values. Linear regression test, adjusted for age, cardiovascular disease status, body mass index (BMI), and education level, with multiple testing correction; #FDR < 0.05, ##FDR < 0.01, ###FDR < 0.001; *FDR < 0.05, **FDR < 0.01, ***FDR < 0.001. FDR, false discovery rate.