Protection of cattle against bovine leukemia virus (BLV) infection could be attained by DNA vaccination

The bovine leukemia virus (BLV) envelope gene encoding extracellular glycoprotein gp51 and transmembrane glycoprotein gp30 was cloned into a vehicle expression vector under the human cytomegalovirus (CMV) intermediate early promoter. The intramuscular injection of this plasmid vector generated a cellular immune response. Seven out of ten cows vaccinated with the DNA construct resisted a drastic challenge (500 BLV-infected lymphocytes as an infectious dose)