The antiviral effects of recombinant bovine interferon-τ (rboIFN-τ) on bovine leukemia virus (BLV) were examined in vitro and in vivo. In the in vitro experiments, BLV titers decreased in FLK-BLV cells and in peripheral blood mononuclear cells of BLV-infected cattle treated with rboIFN-τ at a concentration higher than 102 U/ml. In order to examine the in vivo effects of rboIFN-τ, 10 BLV-infected cattle were subcutaneously injected with rboIFN-τ. In the first experiment, 6 cows were administrated with 105 U/kg body weight of rboIFN-τ 3 times per week for 4 weeks, while in the second experiment 4 cows were administrated with 106 U/kg body weight of rboIFN-τ 3 times per week for 3 weeks. No adverse effects were observed after the administration of rboIFN-τ. In experiment No. 1, the mean BLV titers in cattle decreased in the post- rboIFN-τ administration period compared to the pre- rboIFN-τ administration period. In experiment No. 2, the mean BLV titers in cattle decreased in the rboIFN-τ administration period. These results suggest that rboIFN-τ decreases BLV titers in vitro and in vivo and that rboIFN-τ possibly reduces the degree of BLV titer in cattle without severe side effects.
2007 by the Japanese Society of Veterinary Science