Study Of Linear Neutralizing Epitopes Of Hepatitis E Virus Capsid Protein And Design And Construction Of Epitope-based Vaccine

Hepatitis E Virus(HEV) has emerged to be a dominant cause of acute hepatitis, which is often associated with outbreaks and epidemics in both developing and industrialized countries.Accumulating evidence indicated that hepatitis E was a zoonotic disease.The ability of cross-species infection of HEV raised potential public health concerns for zoonotic HEV transmission which might become a great threat to human health.Researches into this pathogen were not enough to make the mechanisms of HEV replication and pathogenesis clearly understood,this was mainly due to the lack of efficient virus isolation method and cell culture system or a practical animal model.For providing better disease prevention and control program, we need very much to investigate the nature of this antigen and its immune response mechanism.In this research,a pool of anti-HEV antibodies immunized from turncated caspid proteins were fristly studied in detail.Technique used were including epitope identification based on recombinant proteins or overlapping peptide libraries,analysis of competitive inhibition of antigen-antibody reaction,RT-PCR analysis of virus immune capture and analysis of the nature of antibodies based on cell binding model of recombinant proteins which could form virus-like particle or virus-cell adsorption model.Secondly,some representative epitopes were analysised and compared by multiple alignment and mutation analysis,which could help to understand the complex HEV epitopes and be of great importance to vaccine design.Thirdly,in order to enhance the immunogenicity of epitopes,we fully display epitopes by constructing epitope fusion proteins using HBcAg virus-like particles as a vector. Serial analysis of serums from immunized BALB/c mouse demonstrated the 12A10 epitope,one non-immunodominant epitope,had the ability of neutralizing HEV nature virus.The result indicated that this epitope might serve as candidate epitope for epitope-based vaccine design. In conclusion,this thesis attempted to illuminate HEV epitopes based on reconbinant caspid proteins,analysis selected representative epitopes in more details and made a tentative research on epitope-based vaccine design.A vaccine against HEV is not yet available.Existing vaccine candidates were based on modification of HEV caspid protein,rather than epitope-based vaccine design technology.So,this research was not only helpful for in-depth study of HEV epitopes by providing some research methods,but also beneficial to pathological research and vaccine development,which had a good reference value for design of HEV epitope-based vaccine.