Neurothelin: An Inducible Cell Surface Glycoprotein of Blood-Brain Barrier-specific Endothelial Cells and Distinct Neurons

The blood-brain barrier is characterized by still poorly understood barrier and transport functions performed by specialized endothelial cells. Hybridoma technology has been used to identify a protein termed neurothelin that is specific for these endothelial cells. Neurothelin is defined by the species-specific mouse mAb lW5 raised against lentil-lectin-binding proteins of neural tissue from embryonic chick. In the posthatch chick, neurothelin expression is found on endothelial cells within the brain but not on those of the systemic vascular system. Injection of the monoclonal antibody in vivo leads to labeling of brain capillaries, indicating that the corresponding antigen is expressed on the luminal surface of brain endothelial cells. Transplantation of embryonic mouse brain onto the chick chorioallantoic membrane results in rodent brain vascularization by the avian vascular system. Subsequently, normally mAb lW5-negative endothelial cells, originating from blood vessels of the chick chorioallantoic membrane, are induced to express neurothelin when they are in contact with mouse neural