Abstract
The conversion of the Epstein-Barr virus-negative [human lymphoblastoid] Ramos cell line was previously been shown to result in an Epstein-Barr virus-positive non-virus-producer cell line, EBR. Epstein-Barr virus DNA from EBR alone among several cell lines examined was totally unmethylated at 3 of 4 sites containing guanine plus cytosine which were tested. This is in direct contrast to reports of high degrees of methylation in the DNA of other animal viruses, including herpesviruses, isolated from cells in which the viral genome is expressed at a low level.