Leukemogenesis by bovine leukemia virus (BLV)

Bovine leukemia virus (BLV) is a type C retrovirus which is the causative agent of a B cell lymphocytic leukemia horizontally transmitted in cattle (1, 2, 3). This virus was proven to be totally exogenous to its target animal as well as to sheep, goat, mouse, cat, chicken and man (4). It appears to be unrelated, as judged by nucleic acid hybridization and immunological properties, to any other retrovirus tested up to now. However, a slight relatedness between the amino terminal sequence of the major internal protein (p24) of BLV and the corresponding polypeptide (p30) of a murine type C virus has recently been uncovered (5). This suggests the existence of a remote common ancestor for both viruses.