Polyploidization of Epstein-Barr virus (EBV)-carrying lymphoma lines decreases the inducibility of EBV-determined early antigen following P3HR-1 virus superinfection or iododeoxyuridine treatment.

Four tetraploid cell lines were derived from the Epstein-Barr virus (EBV)-carrying, nonproducer Burkitt lymphoma line Raji after colcemide treatment. EBV early antigen (EA) was induced by P3HR-1 virus superinfection and by iododeoxyuridine treatment. Inducibility was reduced in all tetraploid lines compared to the near-diploid counterpart. The average number of EBV genome equivalents per tetraploid cell was 60-70, compared to 50 in diploid cells. This contrasts with the EBV genome amplification previously observed in somatic cell hybrids.