Study On The Immunity Of Recombinant Multiple Epitopes Antigen Of Hepatitis C Virus

Background/Objective: Hepatitis C is an important infectious disease spreading worldwide. At present there is no effective curative and preventive measure against HCV infection, so it is anxious to develop vaccines to control this disease. In order to pave the way for developing HCV therapeutic vaccines, we construct the recombinant polyepitope antigen and study the immunity of it in vitro and in vivo. Method: (1) Highly conserved immunodominant T cell epitopes were selected by biological informatics technology. (2) The genes of multi-epitope were gained through chemosynthesis and inserted into the expression vector pBVILl. (3) The recombinant multi-epitope protein was purified by chromatographic analysis and preparative SDS-PAGE. (4) Balb/c mice were immunized and the antibody titer was tested by ELISA. On the other hand, the T cell response was tested in vitro through ELISPOT and LDH-release assay. (5) Groups of Balb/c mice were subcutaneous injected with SP2/0 cells transferred with partial HCV genes and the protective activity for the pre-immunized mice was observed in vivo.Result: (1) A series of T cell epitopes, which are highly conserved and can cover multiple HLA restriction among most of populations in china were acquired. (2) The recombinant plasmid was correctly constructed. The genes were expressed in E. coli. highly and the expressed protein was purified efficiently. (3) Balb/c mice were immunized with the purified antigen. The high titer antibody was induced. (4) The antigen specific T cell response such as IFN-y release and cytotoxicity to target cells was much stronger in antibody-mediated group than in the other groups. (5) The antigen specific IFN-y release was detected in 9 HCV infected patients' PBMC. (6) In immunized mice, it was detected that a strong correlation of CTL activity with protective efficiency against HCV gene transfected tumor cells, such as inhibition of tumor growth, long lifespan and high life quality.Conclusions: Some progress has been made in selecting and connecting of HCV T cell epitopes. A new immunized program according to the antibody-mediated principle has basically brought through the bottleneck that the protein antigen is difficult to induce the CTL response in vivo. This research can lay promising foundation for the study of HCV therapeutic vaccines.