title: Alpha 4 beta 7 integrin mediates B cell binding to fibronectin and vascular cell adhesion molecule-1. Expression and function of alpha 4 integrins on human B lymphocytes.
abstract: Cell-cell and cell-extracellular matrix interactions are mediated by a wide array of cell surface molecules known as adhesion receptors, including the integrin family that comprises numerous alpha beta heterodimers. A new integrin group, the beta 7 subfamily, has been recently defined. Its two members, alpha 4 beta 7 and alpha H beta 7, are involved in the lymphocyte migration to the Peyer's patches and the intestinal mucosa, respectively. We have analyzed the expression of alpha 4 beta 7 integrin on B cells from different cellular compartments and at different activation states. Resting peripheral blood B lymphocytes constitutively express large amounts of alpha 4 beta 7. By contrast, alpha 4 beta 7 integrin, which is absent on resident B cells from different lymphoid tissues, is induced upon activation. Functional studies indicates that alpha 4 beta 7 is mediating B cell attachment to fibronectin and vascular cell adhesion molecule-1 through distinct epitopes on this integrin. Furthermore, the alpha 4 beta 7 integrin is also implicated in intercellular interactions as deduced by the ability of anti-alpha 4 beta 7 mAb to trigger homotypic B cell aggregation. Finally, alpha 4 beta 7 and alpha 4 beta 1 integrins redistribute at the cell membrane in a similar clustering pattern when B cells attach to fibronectin- and vascular cell adhesion molecule-1-coated surfaces. Our studies demonstrate the differential regulation on the expression and function of alpha 4 beta 7 integrin among different human B cell populations.
authors.affiliation: Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Spain.
authors.forename: A A
authors.initials: AA
authors.lastname: Postigo
authors.forename: P
authors.initials: P
authors.lastname: Sánchez-Mateos
authors.forename: A I
authors.initials: AI
authors.lastname: Lazarovits
authors.forename: F
authors.initials: F
authors.lastname: Sánchez-Madrid
authors.forename: M O
authors.initials: MO
authors.lastname: de Landázuri
mesh_terms: D000951:Antigens, Neoplasm / Q000032:analysis / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002450:Cell Communication; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D039041:Integrin alpha4beta1; D039641:Integrin beta Chains; D016023:Integrins / Q000032:analysis / Q000502:physiology*; D008213:Lymphocyte Activation; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D005353:Fibronectins; D039041:Integrin alpha4beta1; D039641:Integrin beta Chains; D016023:Integrins; D019010:Vascular Cell Adhesion Molecule-1; C091368:integrin beta7