title: HPA-1a alloantibodies reduce endothelial cell spreading and monolayer integrity.
abstract: Maternal human platelet antigen (HPA)-1a alloantibodies causing neonatal alloimmune thrombocytopenia can bind also to endothelium, via the beta3-integrin (CD61). The aim of this study was to investigate the effect of HPA-1a Abs on endothelial cell function, with emphasis on monolayer integrity. We used a CD61 mAb as a model for the HPA-1a alloantibodies and confirmed the results with purified IgG fractions from HPA-1a alloimmunized women. The effect of these antibodies was examined by monitoring the adhesion, spreading, and monolayer integrity of primary HUVECs with conventional adhesion assays as well as electrical cell-substrate impedance sensing. We found that both the mAb CD61 and the HPA-1a antibodies caused a significant reduction in HUVEC spreading. Moreover, addition of the mAb CD61 and the HPA-1a antibodies prior to or following formation of a stable endothelial monolayer negatively affected endothelial monolayer integrity, which was accompanied by a redistribution of junctional proteins. Our data suggest that HPA-1a alloantibodies have a direct effect on endothelial cell spreading and monolayer integrity, which could contribute to the increased bleeding tendency in children with neonatal alloimmune thrombocytopenia.
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Janine M
authors.initials: JM
authors.lastname: van Gils
authors.forename: Janine
authors.initials: J
authors.lastname: Stutterheim
authors.forename: Trynette J
authors.initials: TJ
authors.lastname: van Duijn
authors.forename: Jaap Jan
authors.initials: JJ
authors.lastname: Zwaginga
authors.forename: Leendert
authors.initials: L
authors.lastname: Porcelijn
authors.forename: Masja
authors.initials: M
authors.lastname: de Haas
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hordijk
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D015703:Antigens, CD / Q000378:metabolism; D016824:Antigens, Human Platelet / Q000276:immunology*; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D017097:Electric Impedance; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects; D005260:Female; D006801:Humans; D039661:Integrin beta3; D007518:Isoantibodies / Q000276:immunology*; D014470:Umbilical Cord / Q000166:cytology; D014945:Wound Healing / Q000187:drug effects; D000099152:Cadherin 5
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D016824:Antigens, Human Platelet; D015820:Cadherins; D039661:Integrin beta3; D007518:Isoantibodies; D000099152:Cadherin 5; C061248:ITGB3 protein, human