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. 2021 Jul 15;12:669787. doi: 10.3389/fimmu.2021.669787

Figure 4.

Figure 4

Treg depletion diminishes the protective effect of IL-33 in DSS colitis. To induce intestinal inflammation, BALB/c mice (n = 5-14 mice per group) were given DSS via the drinking water for 6 days. Followed by one day of normal drinking water. On day 0, 2 and 5 control mice as well as DSS mice were injected i.p. either with recombinant mIL-33 or with PBS. Immune cells were isolated from the colonic lamina propria on day 7 and analyzed by flow cytometry to distinguish (A) CD4+Foxp3+ regulatory T cells (Tregs), or (B) lineage-ICOS+ST2+ type 2 innate lymphoid cells (ILC2s). Frequencies and absolute numbers of cells were determined. (C) To induce intestinal inflammation in DEREG/c mice, DSS was given for 6 days, followed by one day of normal drinking water (n = 9-12 mice per group). Tregs were depleted in DEREG/c mice by injecting DT i.p. on day 0, 2 and 5. Mice were additionally treated either with PBS or with recombinant murine IL-33 i.p. on day 1, 3 and 6. (D) Treg ablation was confirmed in the blood on day 0, 4 and 7. (E) Change of body weight and (F) disease activity index were monitored daily. (G) Secretion of IL-33, TNF-α, IL-6, IL-5 and IL-13 in colonic explants was detected by Luminex technology. All data are presented as mean ± SEM. Statistical analyses were performed using one-way ANOVA followed by Dunn’s multiple comparison test (A, B), two-way ANOVA followed by Tukey’s multiple comparison test (D–F), or using one-way ANOVA followed by Tukey’s or Dunn’s multiple comparison test (G). *P < 0.05; **P < 0.01; ***P < 0.001.