Characterization of equine E-selectin

Expression of E-selectin on activated endothelium is a critical initial ste p that leads to extravasation of leucocytes during inflammation, yet E-sele ctin is largely uncharacterized in several animal species including the hor se. We have sequenced and compared E-selectin genes derived from activated cultures of purified equine (horse), cervid (black-tailed deer) and ovine ( sheep) pulmonary artery endothelial cells (ECs). Phylogenetic and amino aci d sequence comparisons indicate that bovine, cervid and ovine E-selectin ar e similar, whereas human and equine E-selectin are more closely related to each other than to the ruminant molecules. Human E- and P-selectin-specific monoclonal antibodies that also recognize equine E-selectin were identifie d and used to characterize its expression. Expression of E-selectin was mor e readily induced by lipopolysaccharide treatment in equine ECs than in hum an ECs and supported adhesion and activation of neutrophils, consistent wit h the extreme sensitivity of horses to endotoxaemia and septic shock.