Establishment and Characterization of Choroid Plexus Carcinoma Cell Lines: Connection between Choroid Plexus and Immune Systems

Murine choroid plexus cell lines were produced from choroid plexus carcinoma generated in transgenic mice harboring the viral oncogene simian virus 40 large tumor antigen under transcriptional control of an intronic enhancer region from the human immunoglobulin heavy chain (IgH) gene. Two morphologically distinct cell lines have been cloned. These established cell lines retained the characteristics of choroid plexus cells in that they expressed such choroid plexus cell marker or related proteins as transthyretin and α(2)‐macroglobulin. They were tumorigenic in nude mice. In the cell lines, the μA and μB (HE2) motifs within the IgH intronic enhancer were active and we also demonstrated the existence of the proteins binding to these motifs, suggesting a potential link between the choroid plexus and immune systems. It is considered that these binding proteins act as trans‐activators for the enhancer and may belong to the class of ETS‐related proteins. These cell lines and xenografts should be useful materials for analyses of choroid plexus functions.