National Veterinary Research and Quarantine Service, Anyang, Gyeonggi-do 430-824, Republic of Korea.
Res Vet Sci. 2010 Oct;89(2):295-300. doi: 10.1016/j.rvsc.2010.03.012. Epub 2010 Apr 7.
Virus-like particles (VLPs) are particles that consist of viral capsid proteins and are structurally similar to authentic virus. To express VLPs of the porcine encephalomyocarditis virus (EMCV) and investigate their efficacy and immuno response in vivo, a plasmid (P12A3C-pCI) containing the P12A and 3C genes of the EMCV-K3 viral strain was constructed. The VLPs of EMCV-K3 were successfully assembled in 293FT cells on 3 days after transfection with P12A3C-pCI and were identified as particles of about 30-40 nm using transmission electron microscopy (TEM). In an in vivo experiment, the murine cytokines induced by VLPs of naked DNA vaccine showed that the Th1 indicators IL-2, TNF-alpha and GM-CSF, and the Th2 indicators IL-4 and IL-10 were increased. The immunization of mice with the P12A3C-pCI plasmid induced high levels of neutralizing antibody from 128- to 256-fold and led to a significant protection ratio (90%) after challenge with EMCV-K3 (wild-type strain). These VLPs may represent a novel vaccine strategy for the control of EMCV infection on pig farms.
病毒样颗粒（VLPs）是由病毒衣壳蛋白组成的颗粒，其结构与真正的病毒相似。为了表达猪脑心肌炎病毒（EMCV）的 VLPs，并研究其在体内的疗效和免疫反应，构建了一个含有 EMCV-K3 病毒株 P12A 和 3C 基因的质粒（P12A3C-pCI）。在转染 P12A3C-pCI 后的第 3 天，293FT 细胞中成功组装了 EMCV-K3 的 VLPs，并通过透射电子显微镜（TEM）鉴定为约 30-40nm 的颗粒。在体内实验中，裸 DNA 疫苗的 VLPs 诱导的鼠细胞因子表明，Th1 指标 IL-2、TNF-alpha 和 GM-CSF 以及 Th2 指标 IL-4 和 IL-10 均增加。用 P12A3C-pCI 质粒免疫小鼠可诱导高水平的中和抗体，效价增加 128-256 倍，并在 EMCV-K3（野生型株）攻毒后产生显著的保护率（90%）。这些 VLPs 可能代表了一种控制猪场 EMCV 感染的新型疫苗策略。
