我国血吸虫疫苗研究进展及应用前景

  目的  利用生物信息学的方法对细粒棘球绦虫EgTPI B、T细胞表位进行预测，为细粒棘球绦虫诊断抗原的筛选提供分子生物学依据。  方法  采用Expasy中的protparam数据库推测EgTPI的理化性质；利用IEDB、ABCpred软件分析B细胞抗原表位。AMPHI法预测Th细胞的抗原表位；使用Jpred 4软件和SWISS-MODEL构建TPI的二、三级结构；应用MEGA 4.0软件比对细粒棘球绦虫TPI和人类TPI、日本血吸虫TPI、肝片吸虫TPI等7种生物的序列。  结果  通过分析得出EgTPI二级结构中直链结构占15.6 %、α 螺旋占38.9 %、转角结构占12.0 %、其他结构占42.2 %；经多序列比对，人类TPI与细粒棘球绦虫TPI一致度仅为40.08 %，较大的差异更有利于形成抗原表位。预测可能的T细胞表位有16-30、71-85、98-119、142-154、178-200；可能的B细胞表位有28-39、50-60、70-80、131-139、150-159、213-231。  结论  EgTPI可能形成T细胞表位区域有5个，B细胞表位的区域有6个，EgTPI抗原表位预测分析为疾病诊断的候选分子筛选奠定分子生物学理论依据。

Bioinformatics analysis and construction of phylogenetic tree of aquaporins from Echinococcus granulosus

  Objective  To predict B- and T-cell epitopes and theirs structure of triosephosphate isomerase (TPI) of Echinococcus granulosus (Eg TPI) using bioinformatics method and to provide evidences for screening Eg antigens in diagnosis of cystic echinococcosis.  Methods  Physicochemical properties of Eg TPI were predicted using protparam database of Expasy system. B-cell epitopes of Eg TPI were analyzed with the ABCpred and IEDB software and T-cell epitopes of Eg TPI were predicted with AMPHI method. The secondary structure and tertiary structure of EgTPI were constructed using Jpred 4 online software and SWISS-MODEL website. Sequence comparison among 7 TPI of Eg, human, Schistosoma japonicum, and Fasciola hepatica were performed using MEGA 4 software.  Results  The proportion of Eg TPI secondary structure were 15.6% for strand, 38.9% for alpha helix, 12.00% for turn, and 42.2% for other structures, respectively. The consistency between human TPI and Eg TPI was only 40.08% and the disparity is in favour of epitope formation. The predicted T-cell epitopes are 16 – 30, 71 – 85, 98 – 119, 142 – 154, and 178 – 200 and the predicted B-cell epitopes are 28 – 39, 50 – 60, 70 – 80, 131 – 139, 150 – 159, and 213 – 231.  Conclusion  Six regions in EgTPI may be considered as B-cell epitopes and 5 regions as dominant T-cell epitopes. These epitopes could be used as the targets for immunological diagnosis and drug therapy.