Humoral and Cellular Immune Responses Induced by Bivalent DNA Vaccines Expressing Fusion Capsid Proteins of Porcine Circovirus Genotypes 2a and 2b
Issued Date
2024-03-01
Resource Type
eISSN
2076393X
Scopus ID
2-s2.0-85188883870
Journal Title
Vaccines
Volume
12
Issue
3
Rights Holder(s)
SCOPUS
Bibliographic Citation
Vaccines Vol.12 No.3 (2024)
Suggested Citation
Meas S., Chaimongkolnukul K., Narkpuk J., Mekvichitsaeng P., Poomputsa K., Wanasen N., Roshorm Y.M. Humoral and Cellular Immune Responses Induced by Bivalent DNA Vaccines Expressing Fusion Capsid Proteins of Porcine Circovirus Genotypes 2a and 2b. Vaccines Vol.12 No.3 (2024). doi:10.3390/vaccines12030324 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/97871
Title
Humoral and Cellular Immune Responses Induced by Bivalent DNA Vaccines Expressing Fusion Capsid Proteins of Porcine Circovirus Genotypes 2a and 2b
Corresponding Author(s)
Other Contributor(s)
Abstract
Porcine circovirus type 2 (PCV2) is the main causative agent of porcine circovirus-associated disease (PCVAD) that profoundly impacts the swine industry worldwide. While most of the commercial PCV vaccines are developed based on PCV genotype 2a (PCV2a), PCV genotype 2b (PCV2b) has become predominant since 2003. In this study, we developed and evaluated DNA-based bivalent vaccines covering both PCV2a and PCV2b. We generated a new immunogen, PCV2b-2a, by combining consensus sequences of the PCV2a and PCV2b capsid proteins (Cap2a and Cap2b) in a form of fusion protein. We also examined whether modifications of the PCV2b-2a fusion protein with a signal sequence (SS) and granulocyte macrophage-colony stimulating factor (GM-CSF) fusing with interleukine-4 (IL-4) (GI) could further improve the vaccine immunogenicity. An immunogenicity study of BALB/cAJcl mice revealed that the DNA vector pVAX1 co-expressing PCV2b-2a and GI (pVAX1.PCV2b-2a-GI) was most potent at inducing both antibody and cellular immune responses against Cap2a and Cap2b. Interestingly, the vaccines skewed the immune response towards Th1 phenotype (IgG2a > IgG1). By performing ELISA and ELISpot with predicted epitope peptides, the three most immunogenic B cell epitopes and five putative T cell epitopes were identified on Cap2a and Cap2b. Importantly, our DNA vaccines elicited broad immune responses recognizing both genotype-specific and PCV2-conserved epitopes. Sera from mice immunized with the DNAs expressing PCV2b-2a and PCV2b-2a-GI significantly inhibited PCV2a cell entry at serum dilution 1:8. All these results suggest a great potential of our PCV2b-2a-based vaccines, which can be further developed for use in other vaccine platforms to achieve both vaccine efficacy and economical production cost.