An EBNA-negative, EBV-genome-positive human lymphoblast cell line in which superinfecting EBV DNA is not maintained.

A human B-lymphoid cell line, designated TG8, which does not express detectable levels of the EBV (Epstein-Barr virus)-associated nuclear antigen (EBNA), yet carries an average of one to two plasmid copies of the P3HR-1 EBV genome has been identified. TG8 can be superinfected by B95-8 EBV, resulting in up to 60-70% of the population becoming EBNA-positive and 20-30% of the incoming EBV genomes becoming circular by 48 hr postinfection. Neither EBNA expression nor the superinfecting viral DNA is maintained in the population. It is concluded that (1) superinfection of this EBV-genome-positive lymphoblast cell line leads to detectable EBNA expression and circularization of the incoming viral genome and (2) the incoming viral genome and detectable EBNA expression are selectively lost, whereas the endogenous viral plasmid DNA is maintained.