Fig 2. IL-37 protects mice from BCG infection.

(A) BCG burden in lung, measured in CFUs, in WT mice and IL-37-Tg mice at every week following i.n. infection with 4×10⁷ viable BCG. Data are presented as the median ± the interquartile range (iQR) and are representative of two independent experiments; Mann-Whitney U test was used for statistical analysis (n = 4 for each time point). (B) Peritoneal macrophages isolated from WT and IL-37-Tg were infected with H37Rv for 1 h at MOI = 5, washed and cultured for indicated time, followed by CFU assay. (C) Peritoneal macrophages were infected with H37Rv for 1 h at MOI = 5, washed and cultured in the absence or presence of different concentrations of recombinant IL-37 for indicated time followed by CFU assay. Data (B-C) are presented as the median ± the interquartile range (iQR) and representative of three independent experiments, with four duplicates each; Mann-Whitney U test was used for statistical analysis. (D) Representative H&E staining of lungs from BCG-infected WT (n = 4) and IL-37-Tg mice (n = 4) at 4 weeks p.i. of two independent experiments with comparable results. Scale bar, 100 μm. *, p<0.05; **, p<0.01.