title: The extrathymic T-cell differentiation in the murine gut.
abstract: The gut epithelial border is in continuous contact with exogenous antigens and harbors a distinctive and very abundant CD8 alpha alpha intraepithelial T-lymphocyte effector population. We describe here the characteristics of these cells that distinguish them from all other T-cell types in the body as well as their functions in local protection. We also describe how these cells differentiate from local precursors present in the gut cryptopatches (CPs) following a pathway of T-cell differentiation unique to the gut wall. Finally, we describe the origin of the precursors of CD8 alpha alpha T cells, which come from the bone marrow in athymic mice but are first imprinted in the thymus in euthymic mice. Indeed, CD3(-)CD4(-)CD8(-) T-cell-committed precursors can leave the thymus before T-cell receptor rearrangements and then colonize the gut CPs, proceeding with their differentiation within the gut wall.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM), U591, Faculté de Médecine René Descarte Paris V, Institut Necker, Paris, France. rocha@necker.fr
authors.forename: Benedita
authors.initials: B
authors.lastname: Rocha
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology