CD4 and colitis: On the other hand, FACS-purified Tregs derived from β2i/MECL-1&β5i/LMP7-deficient, immunocompetent mice suppress CD4+ T-cell-induced colitis upon cotransfer (not shown), indicating that β2i/MECL-1&β5i/LMP7-deficiency does not disable Treg function.