B- and T-cell epitope of triosephosphate isomerase of Echinococcus granulosus: bioinformatics prediction and analysis

  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.