Intracellular state of Epstein-Barr virus DNA in producer cell lines.

The physical state of the Epstein-Barr virus (EBV) DNA in three cell lines which spontaneously produce virus has been characterized. Circular EBV DNA molecules have been found in P3HR-I, B95-8 and M8I cells. The size of the intracellular M8I circular EBV DNA molecules is comparable with the linear virus genome isolated from virus particles but the circular P3HR-I and B95-8 DNA molecules are shorter than the virion DNA . In addition to the circular form, some EBV DNA with physical properties indicative of integrated sequences was found in all three producer cell lines. There was no marked change in the amount of either the circular or integrated forms of EBV DNA when these producer cell lines were grown in the presence of phosphonacetic acid to suppress the spontaneous virus production which occurs in a small percentage of the cells in untreated cultures.