猪丹毒丝菌SpaA重组蛋白制备与表位鉴定OA

[Objectives]The recombinant SpaA protein was obtained from Erysipelothrix rhusiopathiae with a prokaryotic expression system and the linear B-cell epitopes contained in this protein was further identi-fied to provide candidate targets and a theoretical basis for the design of novel epitope vaccines and the estab-lishment of specific diagnostic methods against swine erysipelas.[Methods]The N-terminal domain of SpaA from E.rhusiopathiae strain SE38 was used to clone the SpaA gene of this strain.The inclusion bodies were col-lected and purified after induced expression to obtain the recombinant SpaA protein in the form of inclusion bodies.24 ICR mice aged 4-6 weeks with a weight of 16-20 g were randomly divided into two groups including the immunized group immunized with the recombinant SpaA protein and the control group immunized with PBS,12 in each group.The level of antibody was determined with enzyme-linked immunosorbent assay(ELISA)10 days after the booster immunization and a challenge test was conducted.Online software BepiPred-2.0 was used to predict linear B-cell epitopes,and the polypeptide corresponding to the sequence with the high-est score was chemically synthesized.The reaction between the epitope polypeptide and SpaA hyperimmune se-rum was detected with ELISA,and the association between the epitope and immune protection was analyzed.[Results]The recombinant SpaA protein from E.rhusiopathiae was successfully prepared.The recombinant SpaA protein only in the form of inclusion body induced significant immune protective effects.A linear epitope of SpaA,410SKVEPESPVKVEKPVDEEKPKDQKK434,was identified,which was significantly associated with protective immune responses.[Conclusions]The recombinant SpaA protein of swine erysipelas was successfully prepared from E.rhusiopathiae,and a B-cell epitope highly correlated with immune protection was identified.This epitope has excellent reactivity and can be used for the subsequent development of epitope peptide vac-cines against swine erysipelas.