title: Anti-CD9 antibodies augment neutrophil adherence to endothelium.
abstract: Anti-CD9 antibodies which bind to the CD9 (p24) antigen are known to induce platelet and pre-B-cell aggregation. We show here that human endothelium expresses the CD9 antigen, and anti-CD9 antibodies incubated with endothelium induce a rapid increase in adhesion of neutrophils to endothelium by an action on the endothelial cell. This augmented adhesion is not mediated by glycoprotein IIb/IIIa or by the leucocyte integrins. Binding of anti-CD9 antibody to CD9 induces shedding of the CD9/anti-CD9 complex off the endothelial cell in a time-dependent manner. It is likely that CD9 binding to its ligand induces an activation event within the endothelial cell, resulting in surface expression of a pre-formed adhesive ligand for the neutrophil, or an activation change to a constitutively expressed ligand to render it functional.
authors.affiliation: Department of Immunology, Children's Hospital Medical Centre, Perth, Western Australia.
authors.forename: K D
authors.initials: KD
authors.lastname: Forsyth
mesh_terms: D000906:Antibodies / Q000276:immunology; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology*; D000943:Antigens, Differentiation / Q000032:analysis / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D046508:Culture Techniques; D004730:Endothelium, Vascular / Q000276:immunology*; D006801:Humans; D008562:Membrane Glycoproteins; D009504:Neutrophils / Q000276:immunology*; D060245:Tetraspanin 29; D013997:Time Factors
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D000943:Antigens, Differentiation; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29