日本血吸虫表膜蛋白23kDa的DNA疫苗的研制及其诱导小鼠的保护性免疫

THE PROTECTION OF Sj23 DNA VACCINE ON MICE

目的研究日本血吸虫表膜蛋白23kDa的DNA疫苗及其诱导小鼠的保护性免疫作用。方法以已克隆的质粒pBluescript－Sj23为模板，设计2条引物，经PCR扩增的Sj23基因克隆于真核表达载体pCD中，重组质粒定位注入小鼠骨骼肌，共注射2次，间隔时间9d，第14d处死小鼠，取定位处肌组织，荧光标记检测抗体，证实肌细胞可表达抗原Sj23。大量提取亚克隆后的质粒pCD－Sj23。把雄性BALB／C小鼠分2组，实验组用剂量为100μg／只的质粒DNA（pCD－Sj23）于第1、4、6周免疫接种，第8周2组均以正常尾锄40±2条／只攻击感染，第14周剖杀小鼠。结果与对照组比较，实验组成虫减虫率、减卵率、每条雌虫减卵率分别为33．01％，49．59％，15．70％。结论Sj23有可能成为有价值的候选疫苗，DNA疫苗可作为一种免疫新途径加以研究。

Ohjective To study Sj23 DNA vaccine and its protection on mice. Methods According to the published gene sequence of the Sj23, a pair of primers were designed. With the two primers, Sj23 isolated from Ecoli. TG1 which pBluescript-Sj23 was cloned in was amplified and subcloned into eukaryocyte expression vector. Recombinant plasmid were injected into the muscle of mice. Each of them was injected twice at the same point at a 9-day interval. The mice were killed on the 14th day. By using the technology of hlstochemistry, a Ag-Ab reaction cou1d be observed in the frozen muscular tissue slice. The result indicated that the antigen 23kDa could be expressed on the membrane of muscular cells. Male BALB/C mice were divided into two groups, each of the experimental group was inocuIated at weeks 0, 3,5 by injection with 100μg pCD-Sj23. The mice of experimental group and control group were challenged with 40 normaI cercariae two weeks after final DNA injection. All mice were killed on the 14th week. Results The worm, egg and egg of single female reduction rates were 33. 01 %, 49. 59 % and 15. 70 % respectively in comparison with the control group. Conclusion Sj23 might serve as a potential vaccine and Sj23 DNA vaccine cou1d provide a new approach to develop immunization of S. japonicum.