Synthesis And Immunological Study Of Fluorinated TF-MUC1 Glycopeptide Antitumor Vaccine

Therapeutic vaccines can induce active immunity against tumor cells and will offer new possibilities for cancer immunotherapy.Tumor-associated MUC1 is overexpressed and glycosylated abnormally in most epithelial tumor cells,making tumor-associated MUC1 glycopeptide an important target for tumor vaccine design.The Thomsen-Friedenreich(TF)antigen(Gal?1-3GalNAcaSer/Thr)is a kind of common Tumor-associated carbogydrate antigens(TACAs)on the tumor-associated MUC1.In view of the poor immunogenicity of tumor-associated MUC1 glycopeptides,the MUC1 glycopeptide was modified in this paper.The electronegativity and the van der Waals radius(4.0,1.47 A)of fluorine are better than oxygen(3.5,1.52 A).The introduction of fluorine atoms can enhance the stability of adjacent glycosidic bonds,thereby improving the metabolic stability,solubility and bioavailability of the glycopeptide antigens.In addition,the PDTRP sequence in the MUC1 extracellular domain tandem repeats(VNTRs)has been considered to be an immunodominant domain.Based on the above points,a 6'-fluorinated TF antigen(6FGal?1-3GalNAc?Thr)was synthesized by chemical method firstly,and then the fluorinated TF antigen was introduced into the PDTRP domain by peptide solid phase synthesis(SPPS).After that,the synthetic MUC1 glycopeptide fragment was conjugated with the carrier protein-bovine serum albumin(BSA)which contains T helper epitope to obtain vaccine candidate V1,and the number of glycopeptide coupled to the carrier protein is determined by MALDI-TOF.At the same time,the vaccine candidate V2 containing the native TF antigen was prepared using the same synthetic method,and the immunological activity study in mice was carried out.The results of immunoassay showed that the anti-sera induced by vaccine V1 can recognize the native TF-MUC1 glycopeptide,and the IgG antibody titer(mean value 9050)induced by vaccine VI against TF-MUC1 glycopeptide antigen is higher than the vaccine candidate V2(mean value 7000)containing the native TF antigen.Therefore,the experimental results confirmed that the introduction of fluorine atoms can enhance the immunogenicity of the MUC1 glycopeptide vaccine,and the fluoroglycopeptide conjugate V1 based on the MUC1 VNTRs immunodominant PDTRP can be used as a promising candidate tumor vaccine,which deserves further study.