Design,Synthesis And Immunological Evaluation Of TF Antigen And Its Fluorinated Vaccines

Tumor vaccines have become an ideal tumor.treatment method,and based on the overexpressed structure on the tumor cell surface,tumor-associated carbohydrate antigens(TACAs),they are designed and synthesized to stimulate the body’s immune system and produce immune responses in order to inhibit tumor growth,reproduction and spread,and ultimately kill the tumor.The Thomsen-Friedenreich(TF)antigen is one of the most important tumor targets,and it is overexpressed in colon cancer,breast cancer,bladder cancer,prostate cancer,liver and stomach cancer.However,TF antigens cannot stimulate cellular immunity that can produce high affinity IgG antibodies.Therefore,we need to couple them with carrier proteins containing T cell epitopes,to stimulate cellular immunity and produce effective IgG antibody levels.Since the natural TF antigen is easily degraded by endogenous glycosidase,the integrity of the vaccine carbohydrate antigen is destroyed,and the specific immune response ability is lowered.In recent years,MUC1 related tumor vaccine research shows that the introduction of fluorine atoms not only enhances the immunogenicity of TF antigen,but also effectively improves its metabolic stability and bioavailability.In this paper,amino-galactose hydrochloride and galactose were used as raw materials to synthesize natural and fluorinated TF antigen disaccharide blocks by chemical method.First,six-step and two-step reactions were carried out to obtain fluorinated and natural monosaccharide donors in 31%and 79%yields;then three-step reaction yielded monosaccharide acceptors in 28%yield;The reaction gave fluorinated and natural disaccharide blocks in yields of 42%and 45%,respectively.Next,the chain decapeptide was synthesized by a solid phase synthesis method,and a cyclic peptide skeleton was obtained in a yield of 77%through a three-step reaction.Then,using the Click method,the disaccharide is linked to the cyclic peptide structure to design a polyvalent carbohydrate cluster.The fluorinated and natural glycopeptides are obtained in a yield of 41%and 35%,respectively,in two steps,and then the carrier protein is passed through the squaraine ester linkage to synthesize a tetravalent glycopeptide tumor vaccine.The innovation of this project is to design a multivalent structure using a cyclic peptide,which is to synthesize a tetravalent carbohydrate cluster structure by coupling a carbohydrate antigen with four side chains of four lysine residues in the cyclodecene peptide,aiming to enhance the immune response during the antigen presentation process in order to increase the immunogenicity of the vaccine.In this study,a mouse immunization experiment was carried out on the synthesized polyvalent glycopeptide vaccine,and the titer of the serum obtained by the experiment was measured.The results showed that both vaccines produced a certain level of IgG antibody,and the antibody titers produced by natural and fluorinated vaccine were 1269 and 6646,respectively,indicating that the vaccine we designed successfully produced an immune response in mice,and the fluoro-modified glycopeptide vaccine had higher IgG antibody titer levels than the natural vaccine;When the natural antigen was used as the coating antigen,the antibody titer of the fluorinated vaccine(3802)is higher than the antibody titer of the natural vaccine(1269),indicating that the antibody produced by the fluorinated vaccine can specifically cross-recognize the natural TF saccharide antigen,showing the potential development value of the fluorinated glycopeptide vaccines as tumor vaccines.