BLV proviral DNA in the genome of the target lymphocyte

Integration of bovine leukemia proviral DNA in the genome of infected cells was investigated in cattle affected by either the persistent lymphocytosis or the lymph node tumor form of enzootic bovine leukosis. In persistent lymphocytosis, proviral DNA was found to be integrated at a large number of genomic sites in one-fourth to one-third of circulating leucocytes. In the lymph node tumor form, in contrast, proviral DNA was found to be integrated at one or very few sites in the genomes of a larger fraction of both circulating leucocytes and lymph node tumor cells.