噬菌体表达短肽模拟血吸虫致弱尾蚴特异性抗原表位的研究

目的　从噬菌体随机肽库中筛选模拟血吸虫致弱尾蚴特异性抗原表位的噬菌体克隆 ,并探讨其免疫保护效果。方法　用紫外线致弱尾蚴免疫兔血清IgG筛选以融合蛋白形式在丝状噬菌体外壳蛋白Ⅲ表达的随机 7肽库 ,三轮免疫筛选后获得的噬菌体克隆经皮下免疫小鼠 3次 ,攻击感染 45d后剖杀 ,观察减虫和减卵效果。结果　经三轮筛选 ,特异性结合的噬菌体富集增加了 10 0多倍 ,随机挑取 2 4个噬菌体克隆经ELISA测定 ,有 2 2个克隆能与致弱尾蚴免疫兔血清IgG特异性反应。混合噬菌体克隆免疫小鼠试验的减虫率与减卵率分别为 33.5 7%和 5 6 .0 7% (P均 <0 .0 0 1)。结论　采用噬菌体随机肽库技术可获得模拟致弱尾蚴特异性抗原表位的短肽分子 ,这些短肽分子能诱导一定程度的保护性免疫

Schistosoma japonicum:preparation of peptides mimicking antigenic epitopes of attenuated cercariae using phage-displayed random peptide library

Aim To obtain the short peptides mimicking antigenic epitopes of attenuated cercariae,and explore their immune protection against Schistosoma japonicum(Sj) in mice.Methods Specific IgG was purified from sera of rabbits vaccinated with ultraviolet attenuated cercariae and to immunoscreen a phage random peptide library of 7 amino acid residues displayed as a fusion to protein Ⅲ of filamentous phage.Positive clones were obtained after three rounds of biopanning,the reactivity of each clone binding to specific IgG was assayed by ELISA.Kunming mice were immunized subcutaneously three times with mixed phage clones.45 days after challenge,the mice were perfused,the worms and the liver eggs were counted.Results The eluted phages were enriched more than 100 fold through three rounds of biopanning. Among 24 phage clones randomly selected from the third round biopanning,22 clones of them showed to actually bind to the specific IgG.As compared with the control group,the worm reduction rate and the liver egg reduction rate were 33.57% and 56.07%(P<0.001),respectively.Conclusion It is indicates that antigenic epitopes of attenuated cercariae can be prepared by immunoscreening phage random peptide library and a protective immunity against S.japonicum can be stimulated by these epitopes in mice.