Characterization of ovine lentivirus envelope glycoprotein expressed in Escherichia coli cell and baculovirus systems

The ovine lentivirus (OLV) envelope protein NH2- and COOH-terminal subunits gp70 and the NH2-terminal subunit gp40 were expressed in Escherichia coli cell. The entire gp70 envelope protein was also expressed in insect cells by the recombinant baculovirus. Guinea pigs were immunized with each bacterially expressed recombinant protein, and a serum neutralization assay was used to determine their capacity to neutralize OLV. These results showed that the major neutralization epitopes are located in the NH2-terminal half of the gp70. The baculovirus expressed gp70 was found on the surface of insect cells and was immunobiologically active. Virus neutralization activity was also produced in sheep immunized with the baculovirus expressed recombinant protein.