Recombinant PRV Expressing GP3 and GP5 of PRRSV Provides Effective Protection Against Coinfection With PRV and PRRSV

Area of Science:

• Veterinary Virology
• Immunology
• Biotechnology

Background:

• Porcine Reproductive and Respiratory Syndrome (PRRS) and Pseudorabies (PR) are significant swine diseases.
• Current vaccines offer limited protection against emerging NADC30-like PRRSV and PRV variants.
• Coinfection poses a major threat to the swine industry, particularly in China.

Purpose of the Study:

• To develop a novel vaccine vector for PRRSV and PRV coinfections.
• To construct and evaluate recombinant PRV strains expressing PRRSV antigens.
• To assess the immunogenicity and efficacy of these candidate vaccines in pigs.

Main Methods:

• Utilized HDR-CRISPR/Cas9^D10A for constructing recombinant PRV strains.
• Engineered PRV with TK and gI/gE deletions, expressing fused GM-CSF, GP3, and GP5 proteins from NADC30-like PRRSV.
• Assessed viral growth, genetic stability, and immune responses in cell lines, mice, and piglets.

Main Results:

• Selected four stable recombinant PRV strains expressing target proteins in BHK-21 cells.
• Identified two strains (rPRV-ΔTK-GP3-GP5-eGFP-ΔgI/gE-mCHERRY-B and rPRV-ΔTK-eGFP-ΔgI/gE-GP3-GP5-mCHERRY-B) with superior immunogenicity in mice.
• Demonstrated enhanced PRRSV and PRV-specific immune responses, reduced pathology, and faster recovery in vaccinated piglets.

Conclusions:

• Recombinant PRV serves as a viable viral vector for expressing PRRSV genes.
• The developed PRV-based candidate vaccines show potential for controlling PRRSV and PRV coinfections.
• This study provides a foundation for new vaccine development against these economically important swine diseases.