CD8+CD122+ Regulatory T Cells (Tregs) and CD4+ Tregs Cooperatively Prevent and Cure CD4+ Cell-Induced Colitis.

We identified CD8+CD122+ regulatory T cells (Tregs) and demonstrated their importance in the maintenance of immune homeostasis and in the recovery from experimental autoimmune encephalomyelitis. In this paper, we show that CD8+CD122+ Tregs effectively prevent and cure colitis in a mouse model. In our experiments, colitis was induced in lymphocyte-deficient RAG-2-/- mice by transferring CD4+CD45RBhigh cells that were excluded with CD4+ Tregs. Cotransfer of CD8+CD122+ cells clearly suppressed the development of colitis, and this suppressive effect was similar to that of CD4+CD45RBlow cells that were mostly CD4+ Tregs. CD8+CD122+ cells obtained from IL-10-/- mice were unable to suppress colitis, indicating that IL-10 is an important effect-transmitting factor in the suppression of colitis. CD8+CD122+ cells showed a suppressive effect when they were transferred 4 wk after CD4+CD45RBhigh cells, indicating the therapeutic potential of CD8+CD122+ cells. A mixture of CD8+CD122+ cells and CD4+CD45RBlow cells was far more effective than single Tregs, indicating the synergistic effect of these Tregs. These overall findings demonstrate the potential role of CD8+ Tregs, and possibly together with CD4+ Tregs, in the medical care of inflammatory bowel disease patients. [ABSTRACT FROM AUTHOR]