As previously described [37], Rag1−/− mice transferred with 1 × 105 WT CD4+CD45RBhigh T cells presented progressive loss of body weight and higher colitis activity score (Fig. 5a, b) and showed clinical symptoms of severe colitis including massive infiltration of mononuclear cells in colonic lamina propria, disruption of epithelial boundaries, and disappearance of goblet cells (Fig. 5c). Here, CD4 is linked to colitis.