title: CD4+ CD25+ regulatory T lymphocytes inhibit microbially induced colon cancer in Rag2-deficient mice.
abstract: Inflammatory bowel diseases, including ulcerative colitis and Crohn's disease, increase the risk of colorectal cancer in humans. It has been recently shown in humans and animal models that intestinal microbiota and host immunity are integral in the progression of large bowel diseases. Lymphocytes are widely believed to prevent bacterially induced inflammation in the bowel, and lymphocytes are also critical in protecting against primary tumors of intestinal epithelia in mice. Taken together, this raises the possibility that lymphocytes may inhibit colon carcinogenesis by reducing bacterially driven inflammation. To examine the role of bacteria, lymphocytes, and inflammatory bowel disease in the development of colon cancer, 129/SvEv Rag-2-deficient and congenic wild-type mice were orally inoculated with a widespread enteric mouse bacterial pathogen, Helicobacter hepaticus, or sham-dosed with media only. H. hepaticus-infected Rag2-/-, but not sham-dosed Rag2-/- mice, rapidly developed colitis and large bowel carcinoma. This demonstrated a link between microbially driven inflammation and cancer in the lower bowel and suggested that innate immune dysregulation may have an important role in inflammatory bowel disease and progression to cancer. H. hepaticus-infected wild-type mice did not develop inflammation or carcinoma showing that lymphocytes were required to prevent bacterially induced cancer at this site. Adoptive transfer with CD4+ CD45RBlo CD25+ regulatory T cells into Rag-deficient hosts significantly inhibited H. hepaticus-induced inflammation and development of cancer. These results suggested that the ability of CD4+ T cells to protect against intestinal cancer was correlated with their ability to reduce bacterially induced inflammatory bowel disease. Further, regulatory T cells may act directly on the innate immune system to reduce or prevent disease. These roles for T cells in protection against colon carcinoma may have implications for new modes of prevention and treatment of cancer in humans.
authors.affiliation: Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. serdman@mit.edu
authors.forename: Susan E
authors.initials: SE
authors.lastname: Erdman
authors.forename: Theofilos
authors.initials: T
authors.lastname: Poutahidis
authors.forename: Michal
authors.initials: M
authors.lastname: Tomczak
authors.forename: Arlin B
authors.initials: AB
authors.lastname: Rogers
authors.forename: Kathleen
authors.initials: K
authors.lastname: Cormier
authors.forename: Benjamin
authors.initials: B
authors.lastname: Plank
authors.forename: Bruce H
authors.initials: BH
authors.lastname: Horwitz
authors.forename: James G
authors.initials: JG
authors.lastname: Fox
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015704:CD4 Antigens / Q000276:immunology*; D003110:Colonic Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004195:Disease Models, Animal; D016481:Helicobacter Infections / Q000150:complications*; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000276:immunology / Q000473:pathology; D017710:Lymphocyte Transfusion; D051379:Mice; D018345:Mice, Knockout; D015375:Receptors, Interleukin-2 / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D019895:Transposases / Q000172:deficiency / Q000235:genetics / Q000502:physiology
chemical_list: D015704:CD4 Antigens; D004268:DNA-Binding Proteins; C499308:Rag2 protein, mouse; D015375:Receptors, Interleukin-2; C064655:V(D)J recombination activating protein 2; D019895:Transposases