α-galactosyl-mediated activation of porcine endothelial cells: studies on CD31 and VE-cadherin in adhesion and signaling

摘要: Background.Ligation of α-galactosyl epitopes on endothelial cells by naturally occurring human antibodies causes hyperacute rejection in porcine-to-human xenotransplantation. The α-galactosyl-specific lectin Bandeiraea simplicifolia isolectin B4 (IB4) has been reported to trigger endothelial" gap" formation and tyrosine phosphorylation of an unidentified 130-kDa protein (1, 2). We have studied two 130-kDa junctional adhesion molecules, CD31 and VE-cadherin, in porcine aortic endothelial cells (PAECs) during IB4-mediated activation. The cellular distribution of these molecules, their susceptibility to tyrosine phosphorylation, and their capacity to bind IB4 or natural human antibodies have been determined.Methods.Porcine CD31 and VE-cadherin were cloned. Recombinant proteins and monoclonal antibodies were prepared. The distribution and phosphorylation of CD31 and VE-cadherin in confluent PAECs …