Location: Foreign Animal Disease Research
Project Number: 8064-32000-060-15-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Aug 1, 2017
End Date: Dec 31, 2020
Despite disease control efforts, Porcine Reporductive and Respiratory Syndrome Virus (PRRSV) and Classical Swine Fever Virus (CSFV) remain cause for significant economic losses and remain as major threats to the global swine industry and food security. Classical Swine Fever (CSF) eradication efforts in South Korea using recombinant E2-based vaccines have been successful. However, using live attenuated vaccines is more efficacious for early onset and long duration of immunity. Safety concerns over reversion to virulence of attenuated vaccine strains remains. Therefore, novel porcine-customized approaches are needed to develop more efficacious vaccines for these and other challenging diseases including; overcoming antigenic variation of the pathogen, early onset of immunity, long duration of immunity, safety in individual pigs and herds, and economic and safe production. This research project will investigate porcine cytomegalovirus (pCMV)-based viral vector as a porcine vaccine vector to address these needs. Specific objectives include: 1. Evaluation and selection of one or more avirulent Korean pCMV isolates based on swine safety and immune evasion characterization studies. 2. Establishment of pCMV gene editing and recombinant pCMV construction techniques. 3. Construction and characterization of two recombinant pCMVs; a) Expressing Porcine Reproductive and Respiratory Syndrome Virus protective T cell antigen and b) Expressing Classical Swine Fever Virus protective B cell antigen.
This project focuses in the use of pCMV as a vector vaccine to deliver recombinant antigens as CSFV E2 and PRRS virus antigens. Field naturally attenuated pCMV isolates will be characterized in their level of virulence in pathogenesis studies. Those isolates proven to be attenuated, although still able to mount a specific response, will be genetically characterized by full-length sequence using next generation sequencing ( NGS). The information obtained will be used to develop a methodology, based in CRISP/Cas9 approach, to produce recombinant pCMV. Two different recombinant pCMV will be created harboring recombinant genes; the CSFV major structural glycoprotein E2 and the major T cell epitope from PRRS virus. Recombinant viruses will be evaluated in terms of recombinant protein expression and genetic stability.