title: beta1 integrins are not required for the maintenance of lymphocytes within intestinal epithelia.
abstract: beta(1) integrins are thought to play a central role in maintaining lymphocytes within mucosal epithelia via their interactions with extracellular matrix proteins and subepithelial cellular components within and underlying the basement membrane. In the current study type a (CD8alphabetaTCRalphabeta) and type b (CD8alphaalphaTCRgammadelta and CD8alphaalphaTCRalphabeta) intraepithelial lymphocyte (IEL) subsets within the mouse small intestine were found to express functional beta(1) integrin and the beta(1) integrin alpha chain partners alpha(1), alpha(2), and alpha(4). Using inducible beta(1) integrin-knockout bone marrow-chimeric mice we demonstrate that IEL expression of alpha(1) and alpha(2) but not alpha(4) is dependent on expression of the beta(1) chain. Importantly, deletion of the beta(1) chain in IEL did not alter the number or composition of lymphocytes within the intestinal epithelium. Thus, while IEL express functional beta(1) integrins, these are not required to maintain lymphocytes within intestinal epithelia. This result is discussed in the light of conventional views of intestinal lymphocyte homing and localization.
authors.affiliation: Section of Inflammation and Immunology, Department of Experimental Medical Science, Lund University, Lund, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Marsal
authors.forename: Cord
authors.initials: C
authors.lastname: Brakebusch
authors.forename: Gerd
authors.initials: G
authors.lastname: Bungartz
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fässler
authors.forename: William W
authors.initials: WW
authors.lastname: Agace
mesh_terms: D000818:Animals; D039222:Integrin alpha1beta1 / Q000502:physiology; D019012:Integrin beta1 / Q000235:genetics / Q000502:physiology*; D007413:Intestinal Mucosa / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D039222:Integrin alpha1beta1; D019012:Integrin beta1