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

2002年，我们制备了大量的日本血吸虫钙结合蛋白重组蛋白，并利用重组蛋白制备了抗日本血吸虫钙结合蛋白的单抗，并在猪身上进行了疫苗效果试验。用OUR单抗进行免疫组织化学染色，揭示了日本血吸虫各发育阶段的组织分布和表达变化。尾蚴排泄腺内可见强信号。这似乎解释了Calain疫苗效力的一个可能解释。在我们的猪试验中，我们观察到产蛋量显著减少，然而，蠕虫负担没有减少。在猪实验性感染过程中，不存在对钙蛋白酶抗体产生的增强作用，这可能解释了在猪试验中观察到的副肌球蛋白不如副肌球蛋白那么好的效果。同时对DNA疫苗接种情况进行了调查。作为DNA接种的一种途径，耳垫皮内注射可诱导产生较强的抗体。在我们之前的结果中，Th1显性反应似乎对疫苗效果很重要。为此，我们检测了CpG寡核苷酸对日本血吸虫的保护性免疫作用。CpG治疗的小鼠产生了强烈的Th1反应，并显著减少了肝脏中虫卵肉芽肿的形成。CpG的鼻腔治疗也产生了与肌肉注射相当的强烈效果。考虑到CpG在体内的半衰期较短，需要反复治疗。我们的鼻腔治疗作为一种非侵入性接种，对重复治疗CpG是有好处的。作为与中国同行的合作研究，我们在日本血吸虫病Calain疫苗方面取得了进展，并在我们的研究项目中确定了近期的前景。

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.