Superinfecting Activity of the B95–8 Isolate of Epstein-Barr Virus
The B95–8 isolate of Epstein-Barr virus (EBV) has been characterized as a transforming strain (1). In contrast, the P3HR-1 (HR-1) isolate has been shown to superinfect latently infected cells such as Raji and NC-37 cells (2), Differences in the activities of these strains of EBV have been thought to be, at least in part, due to specific characteristic deletions in the viral genomes (3). A third isolate of EBV, derived from an epithelial (Ad-AH)/epithelial (NPC tumor) hybrid designated NPC-KT has been shown to have both transforming and lytic biological properties (4,5). Recent work in our laboratory has shown that, by using 100x concentrates of culture supernatants, superinfecting activity can be demonstrated for the B95–8 isolate of EBV.