中文摘要：

【目的】克隆和表达了日本血吸虫CyclophilinA（SjCyPA）编码基因cDNA，分析其在日本血吸虫不同发育阶段虫体的表达情况，评估该重组抗原在小鼠体内诱导的抗血吸虫免疫保护效果。【方法】从实验室构建的7天童虫消减cDNA文库中，PCR扩增-EST序列的基因全长cDNA，提交到NCBI，登录号为GQ403666。应用荧光实时定量PCR分析该基因在日本血吸虫不同发育阶段虫体的表达情况，以pET28a（＋）为载体构建重组表达质粒，并在大肠杆菌中表达。诱导、表达、纯化和复性重组蛋白，测定其PPIase活性。利用Western blot检测重组蛋白的抗原性。以重组抗原免疫小鼠，评估其对小鼠诱导的免疫保护效果。【结果】PCR获得了sjCyPA编码基因的全长cDNA，其开放阅读框为519bp。荧光实时定量PCR分析表明，该基因在13d童虫表达量最高，为童虫期高表达基因。构建了重组表达质粒pET28a（＋）-SjCyPA，并在大肠杆菌中成功表达。复性重组蛋白具有PPIase活性。Westernblot试验显示该重组蛋白具有良好的抗原性，在小鼠免疫试验中，与空白对照组比较，免疫组小鼠获得18．72％的减虫率和44．6％的肝脏减卵率。【结论】获得了日本血吸虫童虫期高表达的sjCyPA基因的全长cDNA，成功构建了彤CyPA原核重组表达质粒，在大肠杆菌中成功表达，纯化复性得到有PPIase活性的彤CyPA重组蛋白，并证实该重组抗原在小鼠体内诱导产生了部分免疫保护效果。

英文摘要：

[Objective] The present study was intended to clone a cDNA encoding cyclophilin A in Schistosomajaponicum and subsequently investigate its molecular functions as well as immunoprotective potential as a vaccine candidate for schistosomasis [Method] Polymerase chain reaction （PCR） technique was employed to amplify the full-length cDNA encoding cyclophilin A of schistosomula （Sj CyPA） by employing a schistosomula specific enrichment cDNA library as the template. The expression profiles of Sj CyPA were determined at several different development stages by using real-time RT-PCR. The cDNA containing the open reading frame （ORF） of CyPA was subcloned into a pET28a（＋） vector and the recombinant plasmid was transformed into competent E.coil/BL21 for producing recombinant protein. The PPIase activity of recombinant protein was determined by chymotrypsin-coupled chromogenic assay, and its antigenicity was confirmed by Western blot. The immunoprotective potential immunized by recombinant Sj CyPA in mice was also evaluated in the present study. [ Result ] The length of cDNA containing Sj CyPA ORF is 519 base pairs, encoding 172 amino acids. As determined by real-time PCR, the highest expression of Sj CyPA was observed at the transcript level at 13-day schistosomula stage, indicating that Si CyPA was a abundant expression gene at schistosomula stage. The expressions of Sj CyPA both at transprict level and at protein level were not significantly alternated upon the treatment by cyclosporin A as determined by real time PCR and Western blot. Expectly, chymotrypsin- coupled chromogenic assay confirmed that Sj CyPA had PPIase activity and Western blot indicated that Sj CyPA was able to induce specific antibodies. Additionally, animal experiment showed that 18.72% worm reduction and 44.6% egg reduction were achieved in mice vaccinated with recombinant CyPA protein, respectively. [Conclusion] A full-length cDNA encoding Sj CyPA was obtained and its molecular characterizations were preliminarily investigated. Moreo