日本血吸虫Calpain的DNA疫苗诱导小鼠免疫保护性研究

Protective effect of Calpain DNA vaccine of Schistosoma japonicum Chinese strain in infected Balb/c mice

目的 研究日本血吸虫中国大陆株Calpain的DNA疫苗对Balb/c小鼠的免疫保护性作用。方法 大量制备pVAC质粒DNA和pVAC -CalpainDNA疫苗 ,Balb/c小鼠 5 0只 ,随机均分为对照组和实验组 ,对照组每只小鼠的股四头肌注射接种 10 μgpVAC质粒DNA ,实验组以同样方式注射 10 μgpVAC -CalpainDNA疫苗 ,第 3周加强免疫一次。第 4周每只小鼠经腹部皮肤感染 ( 2 5± 1)条尾蚴 ,感染 6周后剖杀 ,从门静脉灌流收集计成虫数、碎脾计T淋巴细胞总数、从各鼠肝脏的同一部位切下小块肝组织 ,置 5 %KOH溶液消化后 ,计算每克肝组织虫卵数 ,比较减虫率、减雌率和减卵率。于免疫前、第一次免疫后 2周和感染后 2周分别从尾静脉采血 ,用ELISA测定抗体水平。结果 与对照组相比 ,实验组获得 36.84%的减虫率、36.36%的减雌率和 43.31%的减卵率 ,感染后实验组小鼠IgG抗体水平升高幅度大于对照组 ,对照组T淋巴细胞数显著多于实验组。结论 CalpainDNA疫苗可诱导小鼠产生较好的免疫保护作用 。

Objective To observe the protective immunity induced by the Calpain DNA vaccine of S.japonicum Chinese strain in infected Balb/c mice. Methods Preparation of plasmid pVAC DNA and plasmid pVAC-Calpain DNA.Fifty Balb/c mice were randomly divided into two groups;each mouse of control group was injected with 10μg plasmid pVAC DNA by i.m.route;the experimental group was injected with 10μg of recombinant plasmid pVAC-Calpain DNA.Each mouse was immunized at week 1 and 3 and challenged with 25 cercariae of S.japonicum Chinese strain by abdomen skin at week 4.All mice were killed and perfused 6 weeks after challenge;the numbers of recovered worms and hepatic eggs were counted.The sera IgG antibody level of mice before immunization,two weeks after immunization and two weeks after infection were determined with ELISA. Results The worm reduction rate of experimental group is 36.84%,its female worm reduction rate is 36.36% and its eggs reduction rate is 43.31% in comparison with the control group.The IgG antibody level is rising greater in the experimental group after infection than the control group.The numbers of T lymphocytes of the control group are significant greater than that of the experimental group. Conclusion The Calpain DNA vaccine could confer partial protection against a subsequnet challenge of S.japonicum Chinese strain in Balb/c mice and might be a potential DNA vaccine.