Southern blot analysis for viral clonality. Genomic DNA from the rhesus LCV-producing B-cell line LCL8664, Mm256-96 tumor tissue, a cell line derived from the Mm256-96 tumor tissue, and the autologous, rhesus LCV–infected cell line used for intravenous inoculation were separated on a 0.6% agarose gel, transferred to a nylon membrane, and hybridized with a rhesus LCV DNA probe for the terminal repeats. Molecular weight markers in kilobases are shown to the right.