Field evaluation of vaccine candidates against schistosomiasis japonica and molecular analysis of vaccine efficacy

2002年，我们制备了大量日本血吸虫Calpain重组蛋白，并利用重组蛋白制备了抗日本血吸虫Calpain单克隆抗体，并进行了猪疫苗免疫效果试验。利用我们的单克隆抗体的免疫组化显示的组织分布和在日本血吸虫发育阶段的表达变化。在尾蚴的排泄囊中观察到强信号。这似乎解释了钙蛋白酶疫苗效力的可能解释。在我们的猪试验中，我们观察到产蛋量显著减少，但蠕虫负担没有减少。在猪实验感染期间，对钙蛋白酶的抗体产生没有增强作用，这可能解释了在猪试验中观察到的副肌球蛋白的效果不如好。还研究了DNA疫苗接种。耳垫皮内注射作为DNA接种的一种途径，可诱导较强的抗体产生。在我们以前的研究结果中，Th 1-显性应答似乎对疫苗效果很重要。基于此，我们检测了CpG寡核苷酸在日本血吸虫保护性免疫中的作用。用CpG处理的小鼠诱导了强烈的Th 1应答和肝脏中虫卵肉芽肿形成的显著减少。CpG的鼻内治疗也诱导了与肌内注射相当的强烈效果。考虑到CpG在体内的半衰期短，需要重复处理。我们的鼻内治疗作为一种非侵入性接种是很好的重复治疗的CpG。作为与国内同行的合作研究，我们在日本血吸虫病钙蛋白酶疫苗的研究方面取得了一定进展，并对今后的研究工作作了前景。

In the year of 2002, we prepared a large amount of recombinant protein of calpain of Schistosoma japonicum, and by the use of the recombinant protein, we produced monoclonal antibodies to S.japonicum calpain and also tested their vaccine effects in pigs. Immunohistochemistry using our mAbs revealed tissue distribution and changes of expression in developmental stages in S.japonicum. We observed strong signal in the excretory grand of cercariae. This seemed to explain a probable explanation of vaccine efficacy of calpain. In our pig trials, we observed significant reduction in egg production, however, no reduction in worm burden occurred. Durning experimental infection in pigs, there was no booster effect for antibody production to calpain, and this might explain not so good effects as were observed for paramyosin in pig trials. DNA vaccination was also investigated. As a rout of DNA inoculation, intradermal injection at ear pad induced strong antibody production. In our previous results, Th1-dominant responses seem to be important for vaccine effects. In line with this, we tested effects of CpG oligonucleotides in protective immunity to S.japonicum. Mice treated with CpG induced strong Th1 responses and significant reduction in egg granuloma formation in the liver. Intranasal treatment of CpG also induced strong effects comparable to those by intramuscular injection. Considering short half-life of CpG in vivo, repeated treatment is needed. Our intranasal treatment as a non-invasive inoculation is good for repeated treatment of CpG. As a cooperative research with Chinese counterparts, we made progress of calpain vaccine for schistosomiasis japonica, and the near future prospect has been fixed in our research project.