猪繁殖与呼吸综合征病毒GP5基因对猪的DNA免疫  

Immunization in Pigs Vaccined with DNA Encoding PRRSV GP5

作　　者：任慧英[1] 郭鑫[1] 杨汉春[1] 王芳[1] 赵东升[1] 杜希珍[1] 

机构地区：[1]中国农业大学动物医学院/农业部预防兽医学重点实验室,北京100094

出　　处：《中国农业科学》2006年第8期1651-1658,共8页Scientia Agricultura Sinica

基　　金：国家"863"计划课题(2002AA241341);国家"十五"科技攻关计划子课题(2002BA514A-16-05)

摘　　要：目的检测PRRSVGP5DNA重组质粒在猪体诱导的免疫反应以及细胞因子的佐剂效应。方法将表达PRRSVGP5的DNA重组质粒与表达3种细胞因子的重组质粒联合免疫SPF猪,经3次免疫后人工感染PRRSV,检测体液免疫、细胞免疫以及攻毒保护性反应。结果重组质粒pCI-GP5可诱导免疫猪产生中和抗体,效价达1:19.2,并可诱导机体产生较强的细胞免疫,攻毒后组织中PRRSV核酸的检出率下降39%,表明表达PRRSVGP5的DNA重组质粒pCI-GP5可诱导一定的免疫效力。pcDNA-IL-4与pCI-GP5共免可将中和抗体效价提高到1:35.5,且可增强细胞免疫反应,与对照组相比,病毒血症的出现频率减少17%,PRRSV阳性组织检出率下降64%;pcDNA-IL-2与pCI-GP5共免也可增强猪的细胞免疫,与对照组相比,病毒血症的出现频率下降50%,PRRSV阳性组织检出率减少59%;pcDNA-IFN-γ与pCI-GP5共免对病毒血症的出现及病毒在组织中的分布均没有抑制作用。结论动物试验结果表明IL-4及IL-2可作为PRRSVGP5DNA重组质粒的免疫佐剂。[Objective] The aim is to analyze the immune responses and the effects of the cytokines induced by GP5 recombinant plasmids of PRRSV. [Method] SPF piglets were immunized with DNA recombinant plasmids pCI-GP5 which expresses PRRSV GP5 by co-administration of pcDNA-IFN-T, pcDNA-IL-2 and pcDNA-IL-4 for three inoculations. The vaccinated pigs were challenged intranasally with PRRSV B J-4. [Result] DNA immunization with pCI-GP5 resulted in the production of both neutralizing antibodies （1：19.2） and cellular immune responses two weeks after the third immunization. The pCI-GP5 showed significantly better protection from the PRRSV challenge compared with the control plasmid. The protection was characterized with a decrease of 39% PRRSV-positive tissues. In addition, the co-administration of pcDNA-IL-4 increased the immune response induced by pCI-GP5. This immune response was characterized by a significant enhancement of a lymphoproliferative response and a higher percentage of CD4CD8＋T cell, showing a higher viral neutralization titer of 1：35.5, a lower percentage of PRRSV-positive tissues and a significantly decreased frequency of viraemia （a drop of 64% and a drop of 17%, respectively, compared with the control group）. Delivery of pcDNA-IL-2 paired with pCI-GP5 resulted in enhanced cellular immune responses, remarkably reduced percentage of PRRSV-positive tissues and frequency of viraemia （a drop of 59% and a drop of 50%, respectively, compared with the control group）. In contrast, the co-administration ofpcDNA-IFN-T had no adjuvant effects. [Conclusion] The results indicated that IL-4 and IL-2 could be used as adjuvant ofPRRSV DNA vaccine.

关 键 词：猪繁殖与呼吸综合征病毒 DNA重组质粒 细胞因子 免疫反应 

分 类 号：S858.28[农业科学—临床兽医学] S852.65[农业科学—兽医学]