INTEGRATION OF A SHORT EPSTEIN-BARR-VIRUS DNA FRAGMENT IN A B95-8 VIRUS CONVERTED BURKITT-LYMPHOMA LINE EXPRESSING EPSTEIN-BARR NUCLEAR ANTIGENS EBNA2 AND EBNA5

We have analysed the expression of transformation-associated viral ant igens, the Epstein-Barr virus (EBV) DNA content and the phenotypic cha racteristics of two B95-8 virus-converted sublines of the EBV-negative Burkitt's lymphoma (BL) line BL28. The converted lines called E95A-BL 28 and E95B-BL28, respectively, differed in their EBV gene expression. The E95B convertant expressed virus-encoded nuclear antigens EBNA1 to -6 and the membrane protein LMP1, but only EBNA2 and EBNA5 were detec ted by immunofluorescence and immunoblotting in the E95A convertant. O nly the entire BamHI W, Y and H regions could be detected in the E95A convertant by hybridization of Southern blots with probes covering the BamHI C, W, Y, H, F, E, K and Nhet regions of the EBV genome. EBV epi somes were found to be absent in the E95A convertant as seen by Gardel la gels. The E95A convertant retained the phenotypic characteristics o f the EBV-negative parental line, and remained highly clonable in agar ose. In contrast, expression of EBNA1 to -6 and LMP1 was accompanied b y a shift towards a more lymphoblastoid cell line-like phenotype and b y loss of agarose clonability in the E95B convertant.