The construction and immunogenicity analyses of a recombinant pseudorabies virus with porcine circovirus type 3 capsid protein co-expression

Porcine circovirus-associated diseases (PCVADs) and pseudorabies (PR) are highly contagious and economically significant diseases of swine in China. Porcine circovirus type 3 (PCV3) is an emerging swine pathogen of PCVAD. Currently, no PCV3 vaccine is commercially available, and the epidemic caused by it is still spreading worldwide. In this study, we used the PRV variant strain HNX as the parental virus to construct recombinant PRV with TK/gE gene deletion and capsid (Cap) protein co-expression, named HNX-delta TK/delta gE-ORF2. The results revealed that PCV3 Cap protein can be detected in HNX-delta TK/delta gE-ORF2-infected PK-15 cells by both western blotting and immunofluorescence assays. Vaccination with HNX-ATK/AgE-ORF2 did not cause pruritus, ruffled fur, systemic infection, or inflammation (without high expression of interleukin-6 (IL-6) and granulocyte colony-stimulating factor (G-CSF) in plasma). Furthermore, HNX-delta TK/delta gE-ORF2 immunization induced an anti-Cap specific antibody, activated a PRV-specific cellular immune response, and provided 100 % protection to mice against the challenge of the virulent HNX strain. Thus, HNX-delta TK/delta gE-ORF2 appears to be a promising vaccine candidate against PRV and PCV3 for the control of the PRV variant and PCV3.

Automated summary

Porcine circovirus-associated diseases and pseudorabies are highly contagious and economically significant diseases of swine in China. The study identifies a promising vaccine candidate for porcine pseudorabies virus and porcine circovirus type 3, providing immunoprotection against these diseases.