Viral Expression Directs the Fate of B Cells in Bovine Leukemia Virus-Infected Sheep

Abstract
The host immune response is believed to tightly control viral replication of deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV). However, this assumption has not been definitely proven in vivo . In order to further evaluate the importance of the immune response in the BLV model, we studied the fate of cells in which viral expression was transiently induced. Using a dual fluorochrome labeling approach, we showed that ex vivo induction of viral expression induces higher death rates of B cells in vivo . Furthermore, cyclosporine treatment of these animals indicated that an efficient immune response is required to control virus-expressing cells.