CHARACTERIZATION OF A STRAIN OF CEREBRAL ENDOTHELIAL CELLS DERIVED FROM GOAT BRAIN WHICH RETAIN THEIR DIFFERENTIATED TRAITS

SUMMARY A strain of cerebral endothelial cells was established from isolated cortical microvessels of caprine brain. These cells, which are referred to as EC1 cells, can be routinely subcultured to 32 passages without the loss of differentiated morphologic and immunologic traits. The ability to routinely subculture EC 1 cells is an important asset, given that isolated cerebral endothelial cells in mammals generally lose their differentiated traits after only 2 to 3 passages. EC1 cells were shown to contain Factor VIII-related antigen, which is a specific marker for cells of endothelial origin. EC 1 cells morphologically demonstrated a scarcity of pinocytotic vesicles on their apical surfaces, a lack of trans-cytoplasmic vesicles, and the ability to form in culture confluent monolayers with tight junctional complexes. Therefore, EC 1 cells possess specific antigenic and ultrastructural features which classify them as being small vessel endothelial cells of the blood-brain barrier type. Cytogenetic evaluation of EC1 cells demonstrated a normal female goat 60,XX karyotype and confirmed the apparent non-transformed nature of EC1 cells due to the lack of chromosome abnormalities or rearrangements. Using scanning electron microscopy, EC 1 cells were also shown to form confluent monolayers on mixed nitrocellulose filters, a feature that will enable the development of an in vitro system to study trans-endothelial transport. Given that EC1 cells are readily subcultured and grow well on nitrocellulose filters, and that they resemble cerebral endothelium in vivo, it seems evident that EC1 cells can be used as a versatile model for the study of blood-brain barrier function, regulation, and pathology.