ENDOTHELIAL CELL-SURFACE EXPRESSION AND BINDING OF FACTOR-VIII-VONWILLEBRAND FACTOR

  • 1 January 1981
    • journal article
    • research article
    • Vol. 103  (2) , 304-308
Abstract
Factor VIII/von Willebrand factor (FVIII/vWF), a glycoprotein molecular complex found in human plasma, was demonstrated by cell membrane fluorescence to be present on the surface of cultured human umbilical cord vein endothelial cells. The endothelial nature of these cells was established by EM studies that revealed the presence of Weibel-Palade bodies in virtually all cells cultured. A newly developed radioreceptor assay was used to detect FVIII/vWF in the medium taken from these endothelial cell cultures; FVIII/vWF concentration in the medium samples increased with time in culture. FVIII/vWF binding studies showed no significant FVIII/vWF-specific binding to endothelial cell surfaces and did not corroborate a previous report suggesting a FVIII/vWF-specific receptor on human umbilical cord vein endothelium. The presence of FVIII/vWF on endothelial cell membranes and the lack of receptor-mediated binding suggests that the FVIII/vWF either has been absorbed non-specifically to the cell surface or is an integral part of the endothelial cell membrane.