Pseudorabies (PR),
classical swine fever (CSF), and porcine circovirus type 2 (PCV2)-associated disease (PCVAD) are economically important
infectious diseases of pigs.
Co-infections of these diseases often occur in the field, posing significant threat to the swine industry worldwide. gE/gI/TK-gene-deleted
vaccines are safe and capable of providing full protection against PR. Classical swine fever virus (CSFV) E2
glycoprotein is mainly used in the development of CSF
vaccines. PCV2 capsid (Cap)
protein is the major
antigen targeted for developing PCV2
subunit vaccines.
Multivalent vaccines, and especially virus-vectored
vaccines expressing foreign
proteins, are attractive strategies to fight
co-infections for various
swine diseases. The gene-deleted pseudorabies virus (PRV) can be used to develop promising and economical multivalent live virus-vectored
vaccines. Herein, we constructed a gE/gI/TK-gene-deleted PRV co-expressing E2 of CSFV and Cap of PCV2 by fosmid library platform established for PRV, and the expression of E2 and Cap
proteins was confirmed using immunofluorescence assay and western blotting. The recombinant virus propagated in porcine kidney 15 (PK-15) cells for 20 passages was genetically stable. The evaluation results in rabbits and pigs demonstrate that rPRVTJ-delgE/gI/TK-E2-Cap elicited detectable anti-PRV
antibodies, but not anti-PCV2 or anti-CSFV
antibodies. These findings provide insights that rPRVTJ-delgE/gI/TK-E2-Cap needs to be optimally engineered as a promising trivalent
vaccine candidate against PRV, PCV2 and CSFV
co-infections in future.