日本血吸虫Sj32DNA疫苗免疫效果的观察

目的：探讨血吸虫Ｓｊ３２ＤＮＡ疫苗抗血吸虫感染的免疫效果。方法：采用ＰＣＲ技术，人工合成引物，以重组ＤＮＡｐＳｊ３２为模板，扩增出编码３２ｋＤａ天冬酰胺肽链酶，即Ｓｊ３２全长ｃＤＮＡ和引入了起始密码子终止密码子的部分ｃＤＮＡ片段，将其分别克隆到ｐＫＢ－ＣＭＶ，构建真核表达载体ｐＢＫ－Ｓｊ３２－１和ｐＢＫ－Ｓｊ３２－２。采用脂质体介导的基因转移将两种重组ＤＮＡ导入ＮＩＨ３Ｔ３细胞，间接免疫荧光法证实Ｓｊ３２在真核细胞中表达。小批量制备纯化ＤＮＡ，进行动物免疫试验。将两种构建的真核表达载体分别直接ｉｍＢＡＬＢ／ｃ小鼠，共免疫３次，攻击感染后６ｗｋ剖杀小鼠。收集血清，ＥＬＩＳＡ法检测抗体水平，并计数成虫负荷及肝组织虫卵数。结果：ｐＢＫ－Ｓｊ３２－１组与ｐＢＫ－Ｓｊ３２－２组免疫小鼠后的减虫率分别为３８．６％和３０．９％，肝组织减卵率分别为５５．７％和５５．２％，与对照组比较，其间差别均具有极显著性意义（Ｐ＜０．０１）。各ＤＮＡ疫苗免疫组能诱导一定水平的抗血吸虫抗体。结论：Ｓｊ３２ＤＮＡ疫苗可诱导小鼠产生一定程度的保护性免疫力，有可能作为血吸虫疫苗候选抗原分子。

OBSERVATION ON THE EFFECT OF Sj32DNA VACCINE OF SCHISTOSOMA JAPONICUM *

AIM: To explore the protective immunity against cercariae challenge in mice immunized with Sj32DNA vaccine of Schistosoma japonicum. METHODS: Primers were designed and the full length and part cDNA encoding 32 kDa(Sj32) amplified from pSj32 by PCR were cloned into pBK-CMV. Eukaryotic expression vector pBK-Sj32-1 containing full-length Sj32 cDNA and pBK-Sj32-2 containing fragment of Sj32 cDNA were constructed. After selection and identification, two plasmids were transfected into NIH 3T3 cells. The expression of Sj32 in transfected cells was confirmed by IFA. After identification, the two plasmids were prepared and purified on batches. Each BALB/c mouse was vaccinated at weeks 0, 3, and 5, by injection with 100 micrograms of purified Sj32DNA into quadriceps muscle. Mice immunized with constructs and the control mice were challenged four weeks after final DNA injection, and worms and the number of eggs in the liver tissue were counted at 8 weeks after challenge. RESULTS: Perfusion and egg counts showed significant differences in terms of worm reduction rate 38.6%-30.9% and egg reduction rate 55.7%-55.2% between the vaccinated and control mice. CONCLUSION: Sj32 DNA vaccine could result in protection against a subsequent challenge of S. japonicum in mice.