title: Novel alpha 4-integrin ligands on an endothelial cell line.
abstract: The unique combination of adhesion molecules expressed on endothelial cells is thought to mediate the specificity of leukocyte-endothelial cell interactions. In this study, murine endothelial cell lines were used as a model to identify novel adhesion molecules that participate in these cellular interactions. Lymphocyte adhesion to the continuous endothelial cell lines mHEVa and mHEVc required alpha 4-integrin. Interestingly, lymphocyte alpha 4-integrin bound to VCAM-1 as well as an unknown ligand on the mHEVa cell line. We have demonstrated that this VCAM-1-independent adhesion to the mHEVa cells was not mediated by other known alpha 4-integrin ligands (fibronectin, alpha 4-integrin itself, or MAdCAM-1). Two novel alpha 4-integrin ligands (p50 and p10) were isolated from the mHEVa cell line but not the mHEVc cell line by B cell alpha 4-integrin-specific ligand binding of radiolabeled mHEV cell membrane proteins. These results provide the first direct evidence that novel ligands for alpha 4-integrin exist on membranes from endothelial cells.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati, OH 45267-0529, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Tudor
authors.forename: T L
authors.initials: TL
authors.lastname: Deem
authors.forename: J M
authors.initials: JM
authors.lastname: Cook-Mills
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D004730:Endothelium, Vascular / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D039441:Integrin alpha4; D008024:Ligands; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011233:Precipitin Tests; D020033:Protein Isoforms; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology; D013997:Time Factors; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D005353:Fibronectins; D008024:Ligands; D020033:Protein Isoforms; D019010:Vascular Cell Adhesion Molecule-1; D039441:Integrin alpha4