Total Synthesis And Immunological Study Of Thomsen Friedenreich Tumor Vaccine Containing α-Galcer Endogenous Adjuvant

In recent years,cancer immunotherapy has made remarkable developments and improved the treatment methods.Tumor-associated glycoantigens(TACAs),as molecular markers specifically expressed on the surface of tumor cells,are considered promising targets for the design of anti-cancer vaccines.Thomsen Friedenreich(TF)antigen is one of the very important tumor targets,which is overexpressed in colon,breast,prostate,liver and gastric cancers.α-Galactosylceramide(α-GalCer)is a typical iNKT cell agonist.After iNKT cells are activated,they can produce immune response to non-T cell dependent antigens and help B cells achieve the conversion from IgM to IgG.Therefore,KRN7000 can mediate cellular and humoral immunity by activating iNKT cells.The modification of the four components of KRN7000,namely the glycocyclic,glycosidic bond,ceramide and alkyl chain,is a hot topic of research today,and the structural characteristics of Th1/Th2 oriented modifiers are analyzed,but the design of compounds biased toward iNKT immune responses remains a difficult task.The research work in this thesis selected TF antigen among tumor-associated glycoantigens and designed and synthesized a two-component fully synthetic tumor vaccine with a well-defined structure using α-GalCer as an endogenous adjuvant.Firstly,the synthetic route of TF antigen was optimized to obtain TF antigen in 15 % yield after 10 steps using amino galactose as raw material;then,the synthetic route of α-galactose ceramide was improved and the 6-OH of galactose group in α-GalCer was chemically derivatized to obtainα-GalCer derivatives in 1 % yield after 14 steps using pentaacetyl galactose as raw material.After that,the TF antigen was covalently coupled with the α-GalCer derivative to obtain the TF-αGalCer conjugate and prepared as a liposomal vaccine.The immune evaluation was partly performed by measuring the immune activity of five groups of vaccines in 6-to 8-week-old female Balb/c mice.The results showed that the TF-αGalCer liposomal delivery form of the vaccine produced IgG antibody titers of 1800 and IgM antibody titers of 100,much higher than the non-liposomal form,indicating that the liposomal delivery form was able to increase the titer level of the vaccine.α-GalCer adjuvant group and TF/α-GalCer physical mixture group both produced almost no titer,indicating that the endogenous adjuvant α GalCer introduction enhances the immunogenicity of TF antigen.Based on the above results,the tumor-associated glycoantigen-based,iNKT cell agonist as an endogenous adjuvant provides a strategy and basis for the construction of a vaccine for synthetic tumors with a well-defined structure.