CD4 and colitis: In the CD4+CD25−CD62L+ T cell adoptive transfer colitis model, only non-activated non-Treg (CD25−) CD4+ T cells with migratory capacity (CD62L+) were injected in immunodeficient SCID mice, which lack functional T and B cells but have normal numbers of natural killer cells, macrophages, dendritic cells and granulocytes [33], [34].