Bovine leukemia provirus in the DNA of different infected host cells

Bovine leukemia provirus is reported to be integrated in the DNA of different infected mammalian cells. We observed morphological transformation in BLV infected sheep fetal spleen, kidney, thymus and sternal cultures. The presence of BLV specific sequences in their genome was established after digestion with the restriction endonuclease EcoRI and hybridization with a BLV specific probe. Human myeloma ARH77 and myeloid K562 cells infected with BLV were virus productive as detected by a reverse transcriptase assay. The presence of proviral sequences was confirmed after Southern blotting analysis. Restriction digestion by SacI enzyme yielded a complete 8.9 kb BLV provirus in infected ARH77 cells and a smaller 7.5 kb BLV fragment in infected K562 cells.