日本血吸虫重组多表位核酸疫苗的构建与免疫保护效果评估

Construction and immunoprotection evaluation of three multi-epitope DNA vaccines against Schistosoma japonicum

为构建重组日本血吸虫多表位核酸疫苗,并通过小鼠免疫保护试验比较不同重组多表位疫苗诱导的免疫保护效果,筛选并以PCR方法扩增日本血吸虫抱雌沟蛋白(SjGCP)、谷胱甘肽-S-转移酶(Sj28GST)的抗原表位和23ku膜抗原大亲水区(LHD-Sj23)的编码DNA片段,构建了pCMV-LHD-Sj23-BSj28,pCMV-BGCP-LHD-Sj23,pCMV-BGCP-LHD-Sj23-BSj28三种日本血吸虫多表位核酸疫苗;采用肌肉注射法接种昆明系小鼠;用日本血吸虫尾蚴攻击感染后,剖杀小鼠,计算减虫率。结果显示,3种重组的真核表达质粒在免疫小鼠中分别获得了6.30%,14.76%和64.95%的减虫率。表明该重组多表位核酸疫苗可诱导较高的免疫保护效果,获得的三价核酸疫苗pCMV-BGCP-LHD-Sj23-BSj28具有潜在的应用价值。

The aim of the present study was to investigate the coordination effecting protective immunity in mice by connecting LHD-Sj23 with the epitopes of Sj28GST and SjGCP to form multi-epitope DNA vaccines.The epitopes of Sj28GST and SjGCP were analyzed and selected by bioinformatics method.The DNA fragments encoding LHD-Sj23,epitopes of Sj28GST and SjGCP were amplified by PCR,and then subcloned into the eukaryotic expression vector pCMV-Script to construct pCMV-BGCP-LHD-Sj23-BSj28,pCMV-LHD-Sj23-BSj28 and pCMV-BGCP-LHD-Sj23,respectively.All three plasmids were used to vaccinate Kunming mice by intramuscular injection.Mice were challenged by Schistosoma japonicum cercariae,and subsequently killed humanely for counting the number of the adult worm 42 days post infection.The three recombinant DNA vaccines induced worm reduction rates were 6.30%,14.76%,and 64.95% respectively.The recombinant plasmid pCMV-BGCP-LHD-Sj23-BSj28 can induce the highest immunoprotection,indicating its potential to be an candidate vaccine against S.japonicum.The results suggested that the multi-epitope vaccine may be a worthwhile way for vaccine development.