To test if failed suppression of aberrant T cell activity by Tregs contributed to the fatal inflammation in Dohh-ΔT and Dhps-ΔT mice, we transferred naive WT CD45.1+ CD4+ T cells into Rag1−/− recipients to initiate colitis, together with Tregs sorted from WT and Dohh-ΔT mice. Here, CD4 is linked to colitis.