title: Type 1 and 2 T helper cell-mediated colitis.
abstract: OBJECTIVE
  Abrogation of mucosal T cell homeostasis by exaggerated not only T helper 1, but also T helper 2 cells is a major problem that leads to intestinal inflammation. In this regard, it is important to understand these different aspects of mucosal inflammation.
  
  
  RESULTS
  Both T helper 1 and 2 cells play central roles in the induction of mucosal immune responses including secretory IgA antibody production, which would be the most beneficial aspect for the host defense mechanism. T helper 1- and 2-type responses, however, exhibit other roles in the abrogation of intestinal homeostasis. Although it has been shown that T helper 1-type immune responses are key players in the induction of intestinal inflammation in mice colitis models and also in inflammatory bowel diseases in humans, studies in murine colitis models clearly show that T helper 2-type responses are also involved in the pathophysiology of the intestinal inflammation. Both regulatory type T cells and T helper 17 cells are involved to down- or upregulate aberrant T helper 1 and 2 cell responses.
  
  
  CONCLUSIONS
  Understanding the cellular and molecular mechanisms of crosstalk among T helper 1, 2, 17 and T regulatory 1 cells is central for the prevention or treatment of inflammatory bowel diseases.
authors.affiliation: Department of Gastroenterology, Research Institute, International Medical Center of Japan, Tokyo, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Dohi
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Fujihashi
mesh_terms: D000818:Animals; D003092:Colitis / Q000276:immunology* / Q000473:pathology; D006801:Humans; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*