Figure 1. Recruitment of CCR2⁺ monocytes activate ILCs during intestinal infection.

(a) C. rodentium burden in faeces from Ccr2^+/+ and Ccr2^−/− mice. Data represent mean±s.d. (n=5, representative of two independent experiments). (b) Colonic lamina propria mononuclear cells (LPMCs) were isolated from at 0 and 12 days post infection (dpi), and cultured for 24 h. Produced cytokines were measured by ELISA. Data represent mean±s.d. (n=5 from two individual experiments). ND, not detected. (c,d) CCR2^WT and CCR2^DTR mice were infected with C. rodentium and diphtheria toxin (DT; 10 ng g⁻¹ body weight) was injected on 5, 7, 9, 11 dpi. Bacterial burden (c) and mouse mortality (d) are shown. Dots represent individual mice. Results are representative of two independent experiments. (e) Cytokines produced by LPMC at 8 dpi. Data represent mean±s.d. (n=3, representative of three independent experiments). (f) RORγt^GFP/+ mice were infected with C. rodentium. LPMCs were isolated on 8 dpi and Th17 (CD3⁺CD4⁺RORγt⁺) and ILC3 (CD3⁻RORγt⁺) were purified by sorting. IL-22 mRNA expression was assessed by qPCR. Data represent mean±s.d. (n=3, representative of 2 independent experiments). (g,h) CCR2^WT and CCR2^DTR mice were infected with C. rodentium and DT was injected on days 5 and 7. LPMCs were isolated on 8 dpi, and cultured in the presence of heat-killed C. rodentium (MOI=10) for 16 h. IL-22 production in CD4⁻ ILCs (Lin^-Thy-1⁺CD3^-CD4⁻), CD4⁺ ILCs (Lin^-Thy-1⁺CD3⁻CD4⁺) and CD4⁺ T cells (Thy-1⁺CD3⁺CD4⁺) was assessed by flow cytometry (g), and absolute number of IL-22-producing T cells and ILCs are shown in h. (i) Rag1^−/−CCR2^WT and Rag1^−/−CCR2^DTR mice were infected with C. rodentium and DT was injected on days 5 and 7. LPMCs were isolated on 8 dpi and cultured for 24 h. Cytokines were measured by ELISA. Data represent mean±s.d. (n=4, representative of two independent experiments). (j) Mouse mortality of Rag1^−/−CCR2^WT and Rag1^−/−CCR2^DTR mice (n=5) infected with C. rodentium. DT was injected on day 5, 7, 9 and 11 post infection. NS, not significant, *P<0.05, **P<0.01, ***P<0.001 by Mann–Whitney U-test (a–c), Student's t-test (e,h,i) and Log-rank test (d,j).