Ril 21

C57BL/6 mice were treated with 3% DSS in drinking water, and intraperitoneal injected with recombinat mouse IL-21 (rIL-21, carrier free, Biolegend, San Diego, CA), 10 μg/ml/100 μl on day 1, 3 and 5 after DSS-treatment. The body weight change, survival rate and DAI were observed daily. Histological analysis and colon length (cm) were measured on day 6 after DSS-induced colitis.

Mice were obtained from Japan SLC and maintained in specific pathogen-free conditions in our animal facility. All animal experiments were performed according to the protocols approved by the Institutional Animal Care and Use Committee at Waseda University (#2017-A007a, 2018-A090, 2019-A041, 2020-A057, 2021-A003, A22-007, and A23-007). We used 7- to 12-wk-old male or female C57BL/6 mice. Mouse rIL-1β, rIL-2, rIL-4, rIL-6, rIL-21, rIL-23, rTGF-β1, rCXCL13, and anti-ICOS (clone C398.4A) monoclonal Abs (mAbs) were obtained from BioLegend. Mouse rIL-12 and Cellstain CFSE (5- or 6-(N-Succinimidyloxycarbonyl)fluorescein 3’,6’-diacetate) were from Fujifilm Wako Pure Chemistry. mAbs to CD28 (clone 37.51), IL-2 (clone JES6-1A12), IL-4 (clone 11B11), IL-2Rα (clone PC-61.5.3), IL-2Rβ (clone TM-β1), and IFN-γ (clone XMG1.2) were from Bio X Cell. CH-223191, 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) were from Cayman Chemical.