日本血吸虫脂肪酸结合蛋白DNA疫苗诱导小鼠保护性免疫力的研究

目的构建日本血吸虫脂肪酸结合蛋白(Sj14FABP)重组质粒,并观察其在小鼠体内诱导的抗日本血吸虫感染保护作用。方法RT-PCR特异性扩增Sj14FABP基因,将其克隆入真核表达载体pVIVO2,通过PCR、双酶切及测序鉴定。获得的重组质粒pVIVO2-Sj14FABP转染HepG2细胞,间接免疫荧光(IFA)检测蛋白表达;并免疫BALB/c小鼠,30d后攻击感染,感染后45天剖杀,计数检获成虫数和肝脏虫卵数。结果RT-PCR扩增出大小为440bp的Sj14FABP片段,重组质粒经PCR和双酶切后均获得目的片段,转染细胞IFA结果显示有较强荧光。重组质粒免疫小鼠后分别获得24.1%减虫率和27.2%减卵率。结论成功构建和表达重组质粒pVIVO2-Sj14FABP,该核酸疫苗能够诱导小鼠产生部分抗血吸虫感染的保护力。

Protective immunity induced by plasmid DNA encoding fatty acid binding protein of Schistosoma japonicum in mice

Objective To construct the recombinant plasmid including fatty acid binding protein from Schistosoma japonicum (Sj14FABP) and study its immune protection against challenge infection in mice. Methods The Sj14FABP gene was amplified by RT-PCR, and cloned into the eukaryotic expression vector pVIVO2. The recombinant plasmid pVIVO2-Sj14FABP was identified by PCR, restriction enzyme digestion and sequence analysis and applied to transfect HepG2 cells to observe the expression of Sj14FABP in vitro by IFA. The mice were immunized with pVIVO2-Sj14FABP, and challenged with S.japonicum cercariae at the 30th day after the immunization. The worms and eggs were collected and counted at the 45th day after the challenge. Results The Sj14FABP gene was amplified, and the same fragment was obtained by PCR and restriction enzyme digestion with recombinant plasmid. The IFA results showed that Sj14FABP was expressed in HepG2 cells. The worm reduction rate was 24.1% and the reduction rate of eggs per gram liver tissue 27.2%, compared with the control group. Conclusion The recombinant plasmid pVIVO2-Sj14FABP has been constructed and expressed successfully, and it can induce partial immune protection in mice.