In an adoptive T-cell transfer colitis model, delivery of naive CD4+ T cells into immunodeficient recipients results in severe intestinal inflammation that can be prevented by cotransfer of Treg cells.47,48 Adoptive transfer of effector CD25−CD62L+CD4+ WT T cells (naive CD4+) into Rag2−/− recipients resulted in the development of colitis with extensive infiltration of inflammatory cells and significant induction of inflammatory cytokines within the colonic tissue (Fig. 8a–d). Here, CD4 is linked to colitis.