CD4 and colitis: An injection of CD45RC(low) T cells from healthy donors was capable of preventing disease.12 Mottet et al subsequently described CD25-expressing CD4+ T cells that were able to cure established T-cell transfer colitis.13 By the early 2000s, it was clear that a thymically derived CD4+CD25+ T-cell population possessed the ability to suppress autoreactive T cells and eliminate autoimmunity.