血吸虫硫氧还蛋白免疫原性研究Ⅰ日本血吸虫硫氧还蛋白DNA疫苗的构建和鉴定

目的构建日本血吸虫(大陆株)硫氧还蛋白(Trx)DNA疫苗(pcDNA3-SjcTrx),并进行分子生物学鉴定。方法根据日本血吸虫菲律宾株Trx基因序列设计一对引物,上游引物引入BamHI酶切位点和起始密码子ATG,下游引物引入EcoRI酶切位点和终止密码子TCA。以日本血吸虫大陆株成虫总RNA为模板,经反转录-聚合酶链反应(RT-PCR)扩增日本血吸虫大陆株Trx(SjcTrx)编码基因。经双酶切并纯化的PCR产物与经双酶切纯化的pcDNA3质粒DNA片段用T4DNA连接酶连接,克隆入真核表达载体pcDNA3,构建重组质粒pcDNA3-SjcTrx,并经限制性内切酶双酶切、琼脂糖凝胶电泳、PCR检测和核苷酸序列测定进行鉴定。结果SjcTrx编码基因RT-PCR产物约334bp,构建的pcDNA3-SjcTrx重组质粒DNA经限制性内切酶双酶切和PCR扩增产物于琼脂糖凝胶电泳均观察到相同大小基因片段,根据核苷酸序列测定结果推导的氨基酸序列与日本血吸虫菲律宾株和曼氏血吸虫Trx分别有97%和43%的同源性。结论日本血吸虫(大陆株)硫氧还蛋白DNA疫苗构建成功,为开展动物保护性免疫试验创造了条件。

Studies on immunogenicity of Schistosoma thioredoxin Ⅰ. Construction and identification of DNA vaccine of Schistosoma japonicum thioredoxin

ObjectiveTo construct and identify a DNA vaccine of Schistosoma japonicum (Chinese strain) thioredoxin. MethodsAccording to a cDNA sequence of S.japonicum (Philippine strain) thioredoxin, a couple of primers was designed with the BamH I restriction endonuclease site introduced in forward primer with ATG as start condon and EcoR I in reverse primer with TCA as termination codon. The gene encoding S.japonicum (Chinese strain) thioredoxin (SjcTrx) was amplified by RT-PCR using total RNA of schistosome as the template. The PCR products and the pcDNA3 plasmids were digested by restriction endonucleases BamH I and EcoR I. The target DNA fragment were purified and cloned properly into the eukaryotic expression vector of pcDNA3. The recombinant plasmids were then transformed into competent E.coli JM109 and identified by endonucleases digestion, PCR, agarose gel electrophoresis and sequencing. ResultsThe RT-PCR product was around 334 bp judged by agarose gel electrophoresis. The same fragments were obtained by restriction enzyme digestion from the recombinant plasmid and PCR with the plasmid DNA as a template. The recombinant plasmid, designated pcDNA3-SjcTrx, was sequenced and shown to be 97% and 43% identical in deduced amino acid sequences to that of S.japonicum (Philippine strain) and S.mansoni thioredoxin, respectively. ConclusionThe S.japonicum thioredoxin DNA vaccine had been constructed successfully, and further studies will be made in different animal models for its immunogenicity.