日本血吸虫模拟短肽诱导小鼠的免疫保护性研究

目的　研究日本血吸虫模拟短肽对小鼠的免疫保护效果,预测其在抗血吸虫感染中的作用。　方法　用粗提纯大鼠血清IgG为配基对噬菌体肽库进行3轮免疫学筛选。随机挑取噬菌体克隆,检测其特异性并进行序列分析;用阳性克隆免疫小鼠,以40条日本血吸虫尾蚴攻击感染,感染后42d剖杀取虫,计算减虫率和减卵率;用ELISA测定免疫鼠抗体反应。　结果　经过3轮筛选,特异性噬菌体得到有效富集;自动测序仪测序获得2个模拟肽分子;将其用于免疫小鼠后,各免疫组与对照组相比,2个模拟肽混合免疫组的减虫率为34.9%P<0.05,肝内减卵率为67.6%(P<0.001)。 2个模拟肽分子分别免疫小鼠 ,各组的减虫率为31.0%(P<0.05)和14.5%(P>0.05)及肝内减卵率为61.2%(P<0.001)和35.7%(P<0.05)。ELISA检测其免疫组鼠血清特异性IgG抗体滴度均大于1∶6 400以上。　结论　利用噬菌体表面呈现技术获得的2个模拟肽分子均可诱导部分抗日本血吸虫感染的免疫保护力

Studies on the Mimic Short Peptide-based Vaccine:Immunoprotection in Mice against Schistosoma japonicum Infection

OBJECTIVE: To evaluate the immunoprotective effect of the mimic short peptide-based vaccine of Schistosoma japonicum (S.j) in mice. METHODS: Phage random peptide library of 12 amino acids was immunoscreened with purified IgG from sera of rats. Three rounds of biopanning were carried out. The positive clones were randomly selected, detected and sequenced. Kunming mice were immunized with positive clones three times (0, 2, 4 weeks). Each mouse was infected with 40 cercariae after 2 weeks of the 3rd immunization. After 42 days of infection, the mice were killed. Adult worms and the liver eggs were counted. RESULTS: The specific phages binding to IgG were enriched after 3 rounds of biopanning. Two short peptides were obtained. Compared with the control groups, the mixture of two mimic peptides induced 34.9% (P < 0.05) worm reduction and 67.6% (P < 0.001) total liver egg reduction in mice. Two different mimic peptides induced 31.0% (P < 0.05), 14.5% (P > 0.05) worm reduction and 61.2% (P < 0.001), 35.7% (P < 0.05) total liver egg reduction respectively. The specific antibody could be induced by the mimic peptides and detected by ELISA in immunized mice, and the antibody titer reached more than 1:6,400. CONCLUSION: The 2 different mimic peptides obtained by immunoscreening phage random peptide library show partial immunoprotection against S. j infection.