[Interaction of a monoclonal antibody to P-selectin with activated platelets and endothelial cells. Heterogeneity of expressing P-selectin in human aorta endothelial cells].

Monoclonal antibody (MAb) CRC81 against P-selectin, a membrane cell adhesion protein of platelets and endothelial cells (EC), has been obtained and characterized. The antibody selectively interacted with the surface of activated platelets and EC due to the redistribution of P-selectin from intracellular organelles onto the surface by activation. MAb CRC81 could recognize not only human but also rabbit and dog P-selectins. MAb CRC81 was used to establish the heterogeneity of human aorta EC with regard to the P-selectin content. Some of the cells in culture did not contain this protein but were nevertheless positively stained for von Willebrand factor, a specific marker for EC which, similar to P-selectin, is localized in Weibel-Palade's bodies. The proportion of P-selectin negative EC increased dramatically in the course of cell passaging: in primary cultures of aortic EC their content was about 15%, while after the 6th passage it exceeded 90%.