Fig. 3: Aberrant inflammatory response in the colon of IFNR-deficient mice following DSS treatment.

a–c 6–8-week-old WT, single or double IFNR-deficient mice were exposed to 1.5% DSS in drinking water for 7 days, followed by regular drinking water for recovery. a Mice were euthanized on day 8 and immune cell infiltrates in the colon were enumerated by flow cytometry (WT, n = 5; Ifnar1^−/−, n = 5; Ifnlr1^−/−, n = 5; Ifnar1^−/−Ifnlr1^−/−, n = 6). b Neutrophil function was analyzed by evaluating myeloperoxidase (MPO) activity by measuring in vivo luminescence in mice injected with luminescent MPO substrate. Representative images display MPO activity (photon radiance (photons s⁻¹ cm⁻² steradian⁻¹; p/s/cm²/sr) presented as pseudo-color images ranging from red (most intense) to blue (least intense) superimposed over gray photographs. Relative MPO activity measured as photon flux (p/s) normalized to the number (p/s/n) of colon-infiltrating neutrophils (live, CD45⁺CD11b⁺Ly6G⁺) is shown (n = 5). c Fecal lipocalin 2 (LCN-2) levels were measures by ELISA on selected days of experimental DSS-induced colitis (n = 5). Data are representative of two independent experiments (a, c). Symbols represent values of individual mice (a–c). Quantitative data were analyzed using a, b one-way ANOVA or c two-way ANOVA followed by Bonferroni’s multiple comparisons test (a–c) and represent mean values with SEM. a *P = 0.0207 (neutrophils, Ifnar1^−/−); **P = 0.0016 (monocytes, Ifnar1^−/−); *P = 0.0216 (eosinophils, Ifnar1^−/−), *P = 0.0172 (eosinophils, Ifnlr1^−/−); *P = 0.0296 (CD169⁺ macrophages, Ifnar1^−/−), **P = 0.0011 (CD169⁺ macrophages, Ifnar1^−/−Ifnlr1^−/−). b *P = 0.0346 (Ifnar1^−/−), *P = 0.0417 (Ifnlr1^−/−), *P = 0.043 (Ifnar1^−/−Ifnlr1^−/−). ****P ≤ 0.0001. P values are for the indicated animal group compared with control group of WT mice (a, b).