Prediction and identification of epitopes in the Echinococcus multilocularis thrombospondin 3 antigen.

BACKGROUND: Alveolar echinococcosis is an epidemic disease caused by the parasitism of Echinococcus multilocularis (Em) larvae in the intermediate or final host. OBJECTIVE: To identify and analyze B-cell and T-cell (Th1, Th2, and Th17) epitopes of the Em antigen protein thrombospondin 3 (TSP3). METHODS: The amino acid sequence of TSP3 was obtained, and the secondary structural characteristics of TSP3 were predicted using bioinformatics software to further predict its potential T-cell and B-cell epitopes. The spleen lymphocytes of BALB/c mice, which were immunized with the TSP3 protein, were collected for co-culture with B-cell and T-cell antigen small peptides. The B-cell epitopes and T-cell epitope subtypes Th1, Th2, and Th17 were identified as having good immunogenicity. RESULTS: After identification, it was found that the predominant epitopes of B cells existing in TSP3 were T18-33, T45-55, and T110-122. Furthermore, the predominant epitopes of T cells existing in TSP3 were T33-42, T45-55, T80-90, and T110-122 in the T1 subtype, T45-55, T68-77, and T92-104 in the Th2 subtype, and T53-63 and T80-90 in the Th17 subtype. CONCLUSIONS: Six T-cell and eight B-cell dominant epitopes of the TSP3 antigen were revealed; these results may be applied in the development of a dominant epitope vaccine.

Prediction and Identification of Epitopes in the Emy162 Antigen of Echinococcus multilocularis.

INTRODUCTION: Alveolar echinococcosis (AE) is a zoonotic disease caused by the parasitism of Echinococcus multilocularis larvae in the intermediate host or the final host. This study aims to identify and analyze the B-cell and T-cell (Th1, Th2 and Th17) epitopes of E. multilocularis antigen Emy162. METHODS: (1) The secondary structural characteristics of the Emy162 protein were predicted by bioinformatics software to further predict the potential T- and B-cell epitopes. (2) The dominant antigen epitopes were detected by ELISA through the reaction of patient serum with small B-cell antigen peptide and assessing the proliferation of splenic lymphocytes of mice immunized with Emy162. (3) The expression of cytokines in splenic lymphocytes of mice stimulated by small T-cell antigen peptides was detected by ELISA, ELISpot and flow cytometry to enable the identification of the T-cell epitopes. RESULTS: (1) The high-scored T-cell epitopes were located at positions E7-13, E36-41, E80-89, E87-96, E97-106 and E129-139, while B-cell epitopes were located at positions E7-13, E19-27, E28-36, E37-48, E78-83, E101-109, E112-121 and E129-139. (2) The three advanced antigen epitopes of Emy162 were E19-27, E112-121 and E129-139. (3) The four Th1 advanced antigen epitopes of Emy162 were E7-13, E36-41, E80-89 and E129-139. The three Th2 advanced antigen epitopes were E36-41, E87-96 and E97-106. The three Th17 advanced antigen epitopes were E36-41, E87-96 and E97-106. CONCLUSION: (1) The Emy162 protein has advanced antigenicity and numerous potential epitopes. Six T-cell and eight B-cell dominant epitopes were revealed using bioinformatics methods. (2) There are three dominant B-cell epitopes, four dominant Th1 epitopes, three dominant Th2 epitopes, and three dominant Th17 epitopes in the Emy162 antigen.