In experimentally induced colitis models, regulatory CD25+ DP T cells generated in MHCII ko mice, probably arising from SP CD8+ T cells, have been demonstrated to control the colitogenic potential of CD25-CD4+ T cells (26), but data are missing on the in vivo CD4+ Treg-specific functionality in MHCII ko models. The gene discussed is CD8A; the disease is colitis.