日本血吸虫SjCTPI-Hsp70 DNA疫苗与白细胞介素12对水牛的联合免疫保护作用研究

目的 探讨中国大陆株日本血吸虫磷酸丙糖异构酶-热激蛋白（SjCTPI-Hsp70）DNA疫苗联合佐剂白细胞介素-12（IL-12）质粒DNA对水牛的免疫保护作用。 方法 实验采用双盲法，所用疫苗及制剂均在实验结束后解码。将购自非血吸虫病流行区45头8～10月龄健康水牛随机分为 A组（SjCTPI-Hsp70+IL-12，300 μg）、B组（SjCTPI+IL-12， 300 μg）和C组（空质粒pVAX+IL-12， 300 μg）等3组（每组15头），每头牛分别经肩部肌肉注射免疫3次，每次间隔28 d。末次免疫后28 d，每头牛经大腿内侧皮肤感染日本血吸虫尾蚴1 000条。解剖前2 d及当天分别收集粪便1次，用定量法计数虫卵和毛蚴。攻击感染后56 d解剖，用生理盐水经胸主动脉灌冲法收集、计数成虫，检测每克肝组织虫卵数。 结果 A、B组减虫率分别为51.2％和41.5％（χ²=1.89，P＞0.05），减雌虫率分别为48.9％和44.7％（χ²=0.35，P＞0.05），减粪卵率分别为52.1％和38.3％（χ²=3.84，P＜0.05），减毛蚴率为52.1％和33.2%（χ2=7.30，P＜0.01）及减肝卵率为61.5％和42.0％（χ²=7.61，P＜0.01）。 结论 用SjCTPI?鄄Hsp70+IL-12免疫水牛可获得一定的免疫保护性作用。

Protective Effects of Co-Immunization with SjCTPI-Hsp70 andInterleukin-12 DNA Vaccines against Schistosoma japonicumChallenge Infection in Water Buffalo

OBJECTIVE: To induce protective effect of co-immunization with S. japonicum triose-phosphate isomerase fused to heat shock protein 70 (SjCTPI-Hsp70) plasmid and interleukin-12 (IL-12) DNA vaccines against Schistosoma japonicum (Chinese strain) infection in water buffalo. METHODS: Forty-five 8-10 months-old water buffalo from a nonendemic area were divided into three treatment groups each with fifteen buffalo: experimental group A (SjCTPI-Hsp70+IL-12, 300 microg), experimental group B (SjCTPI+IL-12, 300 microg), and control group C (pVAX+IL-12, 300 microg). All buffalo were immunized with a series of 3 intramuscular injections administered once every four weeks. Twenty-eight days postvaccination, water buffalo were percutaneously challenged with 1000 S. japonicum cercariae. Fecal examinations were conducted two days prior, one day prior, and on perfusion day, and the number of hatching miracidia and eggs per gram feces were recorded. Fifty-six days post-infection, the buffalo were sacrificed and perfused via the descending aorta. The recovered adult worms and eggs in liver tissue were counted. RESULTS: Groups A and B showed a worm reduction rate of 51.2% and 41.5% (chi2=1.89, P>0.05)), female worm reduction of 48.9% and 44.7% (chi2=0.35,P>0.05), fecal egg reduction of 52.1% and 38.3% (chi2=3.84,P<0.05), a reduction of miracidia-hatching rate by 52.1% and 33.2% (chi2=7.30, P<0.01), and liver egg reduction of 61.5% and 42.0% (chi2=7.61 , P<0.01), respectively. CONCLUSION: Co-immunization with SjCTPI-Hsp70 and IL-12 DNA vaccines induces protective immunity against S. japonicum in water buffalo.