College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, China.
College of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
Virol J. 2019 May 2;16(1):57. doi: 10.1186/s12985-019-1156-2.
Porcine circovirus type 2 (PCV2) is an economically important viral pathogen for swine industry worldwide. However, current PCV2 vaccines provide incomplete protection against the PCV2d, which has recently emerged as the predominant pathogenic form of PCV2.
To develop a novel DNA vaccine with high efficacy against PCV2d virus, we fused the ORF2 of PCV2d to three copies of the minimum-binding domain of the complement C3 cascade terminal component, C3d-P28. Expression of ORF2 alone (pVO) or fused C3d-P28 (pVOC3) were verified by immunofluorescent assay. Vaccine efficacy was tested by measured the DNA copy and T and B cell immune response.
Vaccination with pVOC3 reduced the levels of PCV2 genomic DNA after pigs were infected with either PCV2b or PCV2d genotypes, produced potent antibodies against PCV2, and stimulated PCV2-specific interferon-γ secreting cells.
Results suggested pVOC3 would be a safe and effective DNA vaccine to confer cross-protection against both PCV2b and PCV2d genotypes in pigs.
猪圆环病毒 2 型（PCV2）是一种对全球养猪业具有重要经济意义的病毒病原体。然而，目前的 PCV2 疫苗不能完全预防 PCV2d 的感染，而 PCV2d 最近已成为 PCV2 的主要致病形式。
为了开发针对 PCV2d 病毒的高效新型 DNA 疫苗，我们将 PCV2d 的 ORF2 融合到三个最小结合域的补体 C3 级联末端成分 C3d-P28。通过免疫荧光检测 ORF2 单独（pVO）或融合 C3d-P28（pVOC3）的表达。通过测量 DNA 拷贝数和 T 和 B 细胞免疫反应来测试疫苗的功效。
接种 pVOC3 后，无论是感染 PCV2b 还是 PCV2d 基因型的猪，其 PCV2 基因组 DNA 水平均降低，产生针对 PCV2 的有效抗体，并刺激 PCV2 特异性干扰素-γ分泌细胞。
结果表明，pVOC3 将是一种安全有效的 DNA 疫苗，可在猪中针对 PCV2b 和 PCV2d 基因型提供交叉保护。
