title: Increased adhesion of human monocytes to IL-4-stimulated human venous endothelial cells via CD11/CD18, and very late antigen-4 (VLA-4)/vascular cell adhesion molecule-1 (VCAM-1)-dependent mechanisms.
abstract: Expression of adhesion molecules on endothelial cells (EC) can be up-regulated or induced by cytokines. The aim of the present study was to investigate the effect of IL-4 on both the expression of adhesion molecules on EC and monocyte adhesion to EC. Flow cytometric analysis showed that VCAM-1 expression on EC was up-regulated after stimulation with IL-4 for 24 h, whereas the expression of E-selectin (formerly called endothelial leucocyte adhesion molecule-1 (ELAM-1)) was not enhanced, and that of intercellular adhesion molecule-1 (ICAM-1) only slightly. The adhesion of monocytes to EC increased to maximum values upon stimulation of EC with IL-4 for 24 h. Coating of monocytes with MoAb against the integrin beta 2-subunit (CD18) significantly inhibited their adhesion to IL-4-stimulated EC; maximal inhibition was found when monocytes were coated with anti-CD18 MoAb in combination with MoAb against CD49d (the alpha-chain of VLA-4), whereas no inhibition was found when monocytes were coated only with MoAb against CD49d. Monocyte adhesion was not significantly inhibited when IL-4-stimulated EC were coated with MoAbs against ICAM-1 or VCAM-1 alone or in combination. Adhesion of monocytes was inhibited to a greater extent when in addition to coating of monocytes with MoAb against CD18 the EC were coated with MoAb against VCAM-1. From these results we conclude that monocytes bind to IL-4-stimulated EC via interaction of CD11/CD18 molecules on the monocytes with an as yet unknown endothelial ligand, and interaction of VLA-4 on monocytes with VCAM-1 on EC.
authors.affiliation: Department of Infectious Diseases, University Hospital, Leiden, The Netherlands.
authors.forename: E M
authors.initials: EM
authors.lastname: Verdegaal
authors.forename: H
authors.initials: H
authors.lastname: Beekhuizen
authors.forename: I
authors.initials: I
authors.lastname: Blokland
authors.forename: R
authors.initials: R
authors.lastname: van Furth
mesh_terms: D015703:Antigens, CD / Q000502:physiology*; D018845:CD11 Antigens; D018821:CD18 Antigens; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D019040:E-Selectin; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D015847:Interleukin-4 / Q000494:pharmacology*; D009000:Monocytes / Q000502:physiology*; D009195:Peroxidase / Q000378:metabolism; D016029:Receptors, Very Late Antigen / Q000502:physiology*; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D015703:Antigens, CD; D018845:CD11 Antigens; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D019040:E-Selectin; D016029:Receptors, Very Late Antigen; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D015847:Interleukin-4; D009195:Peroxidase