RAG1 and colitis: CD4+ T cells obtained from the mLNs of R23FR mice in remission (primed by TAM-induced IL-23 and Red 40 treatment) were used to transfer colitis to Rag1−/− mice treated with Red 40 in their drinking water (0.25 g/L) or diet (0.25 g/kg, TD.160647, diet 2019) (Fig. 1A) [12].