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

A strain of cerebral endothelial cells was established from isolated c ortical 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 abi lity to routinely subculture EC1 cells is an important asset, given th at isolated cerebral endothelial cells in mammals generally lose their differentiated traits after only 2 to 3 passages. EC1 cells were show n to contain Factor VIII-related antigen, which is a specific marker f or cells of endothelial origin. EC1 cells morphologically demonstrated a scarcity of pinocytotic vesicles on their apical surfaces, a lack o f trans-cytoplasmic vesicles, and the ability to form in culture confl uent monolayers with tight junctional complexes. Therefore, EC1 cells possess specific antigenic and ultrastructural features which classify them as being small vessel endothelial cells of the blood-brain barri er type. Cytogenetic evaluation of EC1 cells demonstrated a normal fem ale goat 60,XX karyotype and confirmed the apparent non-transformed na ture of EC1 cells due to the lack of chromosome abnormalities or rearr angements. Using scanning electron microscopy, EC1 cells were also sho wn to form confluent monolayers on mixed nitrocellulose filters, a fea ture that will enable the development of an in vitro system to study t rans-endothelial transport. Given that EC1 cells are readily subcultur ed and grow well on nitrocellulose filters, and that they resemble cer ebral endothelium in vivo, it seems evident that EC1 cells can be used as a versatile model for the study of blood-brain barrier function, r egulation, and pathology.