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T cell‐mediated immunoregulation in the gastrointestinal tract
Author(s) -
Saurer L.,
Mueller C.
Publication year - 2009
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.2009.01965.x
Subject(s) - foxp3 , intraepithelial lymphocyte , immune system , immunology , acquired immune system , biology , il 2 receptor , antigen , innate lymphoid cell , t cell , regulatory t cell , innate immune system , t cell receptor , cd8
In the intestinal tract, only a single layer of epithelial cells separates innate and adaptive immune effector cells from a vast amount of antigens. Here, the immune system faces a considerable challenge in tolerating commensal flora and dietary antigens while preventing the dissemination of potential pathogens. Failure to tightly control immune reactions may result in detrimental inflammation. In this respect, ‘conventional’ regulatory CD4 + T cells, including naturally occurring and adaptive CD4 + CD25 + Foxp3 + T cells, Th3 and Tr1 cells, have recently been the focus of considerable attention. However, regulatory mechanisms in the intestinal mucosa are highly complex, including adaptations of nonhaematopoietic cells and innate immune cells as well as the presence of unconventional T cells with regulatory properties such as resident TCRγδ or TCRαβ CD8 + intraepithelial lymphocytes. This review aims to summarize the currently available knowledge on conventional and unconventional regulatory T cell subsets (Tregs), with special emphasis on clinical data and the potential role or malfunctioning of Tregs in four major human gastrointestinal diseases, i.e. inflammatory bowel diseases, coeliac disease, food allergy and colorectal cancer. We conclude that the clinical data confirms some but not all of the findings derived from experimental animal models.