CD4 and inflammation: 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).