Chen Guang-Lei, Fu Peng-Fei, Wang Lin-Qing, Li Xin-Sheng, Chen Hong-Ying
1 College of Animal Science and Veterinary Medicine, Henan Agricultural University , Zhengzhou, Henan Province, People's Republic of China .
Viral Immunol. 2014 Dec;27(10):521-8. doi: 10.1089/vim.2014.0036.
In this study, two recombinant plasmids containing the ORF2 gene of porcine circovirus type 2 (PCV2) with or without porcine interleukin-18 (IL-18) were constructed and evaluated for their ability to protect piglets against PCV2 challenge. Transient expression of the plasmids in PK-15 cells could be detected using Western blot. Piglets were given two intramuscular immunizations 3 weeks apart and were challenged with a virulent Wuzhi strain of PCV2 at 42 days after the initial immunization. All animals vaccinated with pBudCE4.1-ORF2 or with pBudCE4.1-ORF2/IL18 developed PCV2-specific antibody and T-lymphocyte proliferative responses. The levels of T-lymphocyte proliferation in piglets immunized with pBudCE4.1-ORF2/IL18 were significantly higher than in those immunized with pBudCE4.1-ORF2, and pBudCE4.1-ORF2/IL18 stimulated a significantly increased production of IFN-γ and IL-2. Furthermore, PCV2 challenge experiments showed that the DNA vaccine-immunized groups can partially prevent PCV2 viremia and significantly reduce the amount of PCV2 virus in the lymphoid tissues, and the piglets immunized by pBudCE4.1-ORF2/IL18 exhibit a marked inhibition of PCV2 replication compared to the pBudCE4.1-ORF2 group. These data demonstrate that the plasmid pBudCE4.1-ORF2/IL18 may be an effective approach for increasing PCV2 DNA vaccine immunogenicity.
在本研究中，构建了两个分别含有或不含有猪白细胞介素-18（IL-18）的猪圆环病毒2型（PCV2）ORF2基因的重组质粒，并评估了它们保护仔猪抵抗PCV2攻击的能力。使用蛋白质免疫印迹法可检测到质粒在PK-15细胞中的瞬时表达。仔猪每隔3周进行两次肌肉注射免疫，并在初次免疫后42天用PCV2的强毒武陟株进行攻击。所有接种pBudCE4.1-ORF2或pBudCE4.1-ORF2/IL18的动物均产生了PCV2特异性抗体和T淋巴细胞增殖反应。用pBudCE4.1-ORF2/IL18免疫的仔猪的T淋巴细胞增殖水平显著高于用pBudCE4.1-ORF2免疫的仔猪，并且pBudCE4.1-ORF2/IL18刺激了IFN-γ和IL-2的显著增加分泌。此外，PCV2攻击实验表明，DNA疫苗免疫组可以部分预防PCV2病毒血症，并显著减少淋巴组织中PCV2病毒的数量，与pBudCE4.1-ORF2组相比，用pBudCE4.1-ORF2/IL18免疫的仔猪对PCV2复制表现出明显的抑制作用。这些数据表明，质粒pBudCE4.1-ORF2/IL18可能是提高PCV2 DNA疫苗免疫原性的有效方法。
