Construction Of The Recombinant Herpesvirus Expressing E2Genes Of BVDV-1and BVDV-2

Bovine viral diarrhea (BVD) is the disease caused by Bovine Viral Diarrhea Virus (BVDV), which is characterized by bovine viral diarrhea-mucosal disease (BVD-MD), persistent infection, immunotolerance, reproductive problems, thrombocttopenia and hemorrhagic syndrome. BVDV infection endemic worldwide and the natural hosts of BVDV vary from cattle and pigs to many wild animals, like sheep and deer, which results in a considerable financial loss. The persistent infectious animals could eliminate the virus into the environment around all their lives, which is one of the most important sources for BVDV existing in the nature.Although vaccination is still considered as the efficient way to control BVD till now, none commercial standard vaccine is employed in our country. However, lots of researchers have developed novel vaccine of BVDV in multiple ways and made great progress in other countries, including subunit vaccine, DNA vaccine, live recombinant vector vaccine and so on. E2glycoprotein is the main protective antigen of BVDV, which can mediate virus-neutralizing reaction. Therefore, it’s the primary choice for target protein of the new vaccine and live vector vaccine of BVDV containing E2gene has a promising expectation. Moreover, expressing and immunogenicity of the E2gene of Pestivius is always the focus worth studying.BHV-1is an enveloped, double-stranded DNA virus classified as a member within the Alphaherpes subfamily. The BHV-1genome is approximate138kb long, of which the thymidine kinase (TK) gene is the major virulence gene, but not essential in viral replication. According to the report, the TK defective herpes viruses have much lower pathogenicity, but normal replication ability. BHV-1has various advantages as the live virus vector. Firstly, it’s safe to people. Then it has a large genome which could accept some foreign genes. Lastly, it can just infect few kinds of animals. All of this makes BHV-1a potential live virus vector candidate for economically important bovine diseases.Due to the antigenic heterogeneity between BVDV-1and BVDV-2, the vaccine for protecting BVDV-1is invalid to BVDV-2. Hence, it makes sense to construct the recombinant virus which can express E2glycoproteins of BVDV-1and BVDV-2. Considering the safety and immunogenicity of the vaccine, the virus vector vaccine is more ideal compared to the inactivated and live attenuated ones.In this study, we constructed the thymidine negative (TK-) BHV-1recombinant expressing E2genes of both BVDV-1and BVDV-2as a virus vector vaccine candidate of BVDV.