The Epstein-Barr virus (EBV) is a human oncogenic herpesvirus that has been closely linked to nasopharyngeal carcinoma (NPC). It is known that the EBV genome is associated with the epithelial cells of the tumor. In order to study the relationship of the EBV genome with epithelial cells, transfection experiments using whole EBV DNA and restriction endonuclease fragments of EBV DNA, will be performed. Preliminary data suggest that we have had success in transfecting a human epithelial cell line. After optimizing transfection conditions, the expression of the EBV genome in target cells will be studied in an attempt to examine the expression of whole EBV DNA and the function of cloned and defined EBV DNA fragments. Studies are designed to assay for EBV specific antigens, DNA, transcription and polypeptide synthesis in transfected cells in which either lytic replication of EBV occurs or in morphologically transformed cells.