日本血吸虫组织蛋白酶B DNA疫苗与IL-4真核表达质粒联合免疫诱导小鼠保护性的研究

目的　观察日本血吸虫组织蛋白酶BDNA疫苗与IL 4真核表达质粒联合免疫小鼠的效果。　方法　将小鼠IL 4基因PCR扩增片段克隆入真核表达载体pcDNA3以构建重组表达质粒。小鼠分为 4组 ,每组 12只 ,实验组 (A)每鼠肌注组织蛋白酶BDNA疫苗和IL 4表达质粒各 10 0 μg ,同时设立组织蛋白酶BDNA疫苗对照组 (B)、IL 4表达质粒对照组 (C)和空载体对照组 (D) ,共免疫 3次。 2周后用免疫组化检测表达质粒在小鼠肌细胞的表达 ,3周后经皮肤攻击感染小鼠 40± 1条日本血吸虫尾蚴。计算减虫和减卵率 ,观察免疫保护性。　结果　重组IL 4质粒和组织蛋白酶BDNA疫苗均在小鼠肌细胞表达。用重组IL 4质粒和组织蛋白酶BDNA疫苗联合免疫诱导小鼠产生 43 .2 0 %的减虫率和 76.63 %的减卵率 ,与组织蛋白酶BDNA疫苗单独免疫比较差异均有显著性 (P <0 .0 0 1,P <0 .0 5 )。　结论　联合IL 4表达质粒免疫可能提高日本血吸虫组织蛋白酶BDNA疫苗的抗血吸虫保护性免疫。

PROTECTIVE IMMUNITY TO SCHISTOSOMA JAPONICUM ELICITED BY CO-IMMUNIZATION OF CATHEPSIN B DNA VACCINE WITH EUKARYOTIC PLASMID ENCODING IL-4

Objective To examine the efficacy of co-immunization of cathepsin B DNA vaccine of Schistosoma japonicum(Sj) with plasmid encoding IL-4 in mice. Methods The recombinant plasmid was constructed by cloning PCR amplified murine IL-4 gene into eukaryotic expression vector pcDNA. Mice were divided into 4 groups. The test group was intramuscularly injected 100 μg per mouse of each cathepsin B DNA vaccine and plasmid encoding IL-4 while 3 control groups injected with cathepsin B DNA vaccine alone, plasmid encoding IL-4 and vector respectively were set up at the same time. Three times of immunization of mice were followed by determination of muscular cell expression of the interests with immunohistochemistry 2 weeks later and percutaneously challenging mice with 40±1 Sj cercariae 3 weeks later. Immune protection was assessed by worm and egg reduction rates. Results The recombinant mIL-4 plasmid and cathepsin B DNA vaccine were expressed in muscular cells of the immunized mice. Co-immunization of cathepsin B DNA vaccine with plasmid encoding mIL-4 elicited 43.20% of worm reduction rate and 76.63% of egg reduction rate, showing significant difference(P<0.001, P<0.05 respectively) compared with immunization of cathepsin B DNA vaccine alone. Conclusion The protective immunity against S. japonicum induced by cathepsin B DNA vaccine might be improved by co-immunization with plasmid encoding IL-4.