Identification of combined T-cell and B-cell reactive Echinococcus granulosus 95 antigens for the potential development of a multi-epitope vaccine

Liang Wang, Jian Gao, Xi Lan, Hui Zhao, Xiaoqian Shang, Fengming Tian, Hao Wen, Jianbing Ding, Li Luo, Xiumin Ma


Background: Identification of combined T-cell and B-cell reactive Eg95 antigens for the potential development of a multi-epitope vaccine against Echinococcus granulosus (EG), the causative agent of cystic echinococcosis (CE).
Methods: This study involved the recombinant expression of Eg95 along with associated immune rabbit antiserum preparation. Bioinformatics technology was used to facilitate the analysis of Eg95 molecules. PCR was subsequently used to amplify genetic sequences of the epitopes encoding the T-cell and B-cell reactive peptide fragments. SDS-PAGE was used to assess the expression levels of three proteins. Eg95 serum and patient antiserum, which were assessed using Western blot in order to identify suitable antigenic epitope peptides. ELISA detection assay facilitated comparison of the immune reactivity of the short peptide epitopes. The assay results could be used to determine an EG epitope-based vaccine candidate list from suitably reactive Eg95 epitopes.
Results: Eg95 molecules have 3 T-B table. The phage display systems were successfully built using the M13KE carrier. Expression of the three fusion protein peptides were detected. Western blot showed Eg95 antiserum against EG facilitated identification of the three T-cell and B-cell reactive epitopes. After the reaction intensities analyzed by the ELISA, both of the short peptide epitopes Eg95-2 and Eg95-3 showed strong signal strength and associated antigenicity when combined with patient serum and rabbit anti-rEg95 serum.
Conclusions: This study used bioinformatics methods to construct successfully a T-cell and B-cell epitope phage display system for the Eg95 antigen from EG. The two epitopes of Eg95-2 and Eg95-3 demonstrated strong antigenicity with potential applications for peptide vaccine development.