PRRSV GP5蛋白及猪IL-18基因共表达核酸疫苗免疫原性试验

Immunogenicity of DNA vaccine co-expressing swine IL-18 and GP5 protein of porcine reproductive and respiratory syndrome virus

本试验通过分子克隆技术分别构建了单独表达猪繁殖与呼吸综合征病毒(PRRSV)GP5基因以及PRRSVGP5基因和猪IL-18基因共表达的重组核酸疫苗质粒(pEGFP-GP5和pEGFP-IL18-GP5),并进行仔猪免疫原性研究,对构建的PRRSV核酸疫苗所诱导的体液免疫和细胞免疫水平进行检测,进一步研究了PRRSV核酸疫苗免疫效果以及猪IL-18基因对PRRSV核酸疫苗免疫调节作用的影响。同时,调查了商业上应用不同类型的PRRSV疫苗诱导的免疫效果,并与核酸疫苗免疫效果进行比较。结果表明,IL-18作为免疫佐剂在疫苗免疫猪后诱导的病毒特异性细胞免疫反应方面具有很好的调节作用,共表达IL18-GP5蛋白能够明显的改善DNA疫苗的免疫效力,增强抗PRRSV的免疫保护。因此,DNA疫苗做为一种新一代疫苗可用于对抗高致病性PRRSV感染。

Two different kinds of DNA vaccine which express GP5 of porcine reproductive and respiratory syndrome virus （PRRSV）alone and co-express GP5 and swine IL-18 genes（pEGFP-GP5 and pEGFP-IL18-GPS） were con- structed by the molecular cloning techniques and researched for immunogenicity in piglets. Their abilities to induce humoral and cellular responses were evaluated and further more the immune effects of PRRSV DNA vaccine and the role of swine IL-18 in the modulation of PRRSV DNA vaccine-induced immune responses were researched. Mean- while, the immune efficacy in different types of commercial vaccines against PRRSV was compared with the efficacy of DNA vaccine. These results demonstrated that IL-18 as immunologic adjuvants has a positive effect on the activa- tion of vaccine-induced virus-specific cellular immune responses in swine,and co-expression of GP5 and IL-18 protein can significantly improve the potency of DNA vaccine and the immunoprotection of anti PRRSV. So the DNA vaccine could be used as a strategy to develop a new generation of vaccine against highly pathogenic PRRSV.