Chemical Synthesis And Immunological Evaluation Of MUC1 Glycopeptide Based Cancer Vaccines

With the influence of many factors,the tumor is becoming the first killer threatening human health.Different from traditional tumor treatments,tumor immunotherapy has gradually developed into a safe and effective strategy for cancer therapy.Among cancer immunotherapies,the chemical synthetic therapeutic anti-tumor vaccine has the advantages of defined molecular structure,uniform composition,easy preparation and reduced side effects,and gradually develops into a new generation of cancer immunotherapy strategy.The variable number of tandem repeats of MUC1 protein in tumor cells are considered to be an important and ideal target for the development of cancer vaccines.However,the tumor associated MUC1 glycopeptide antigen bears with low immunogenicity and it is difficult to induce an effective antitumor immune response.To address this problem,in this thesis,we chemically introduced different immunostimulatory components into the vaccine system.With the adjuvant effects of immunostimulators,the immunogenicity of glycopeptide antigens was significantly improved,and the tumor specific immune responses were achieved.To enhance the efficacy of two-component MUCl glycopeptide tumor vaccines containing T cell epitope,we prepared different chitosan nanoparticles and mixed them with the MUC1 glycopeptide antigens to form cancer vaccines.These chitosan nanoparticles had strong immune adjuvant effects and significantly increase the immunogenicity of MUC1 glycopeptide antigen.These vaccines effectively activated the immune system in mice,producing high quality of antibody immune responses.The adjuvant activity of chitosan/γ-PGA nanoparticles is superior to chitosan/TPP nanoparticles and Freund’s adjuvant,and it is a safe and efficient vaccine adjuvant.In order to enhance the immunogenicity of the tumor MUC1 glycopeptide,the potent stimulator of NKT cells,the α-galactosylceramide,was modified and conjugated with different glycosylated tumor MUC1 glycopeptide antigens to construct novel self-adjuvanting two-component cancer vaccines.These vaccines effectively enhanced the immunogenicity of the MUC1 glycopeptide without external adjuvants,produced specific immune response against MUC1 antigen in mice.Meanwhile,di-glycosylation of MUC1 glycopeptide could further improve the immunogenicity for stronger immune activation.To explore the multivalent effect in antigen and antibody recognition,we chemically modified β-cyclodextrin and then covalently coupled with multiple Tn glycosylated and truncated MUC1 glycopeptides to form heptavalent MUC1 glycopeptide dendrimers based on β-cyclodextrin.Then we synthesized a two-component vaccine containing a T cell epitope derived from tetanus toxin and the truncated MUC1 glycopeptide.The serum containing the antigen-specific antibody was collected after mice immunization.By utilizing the β-cyclodextrin-MUC1 conjugates and collected antiserum,we confirmed that the antibody has the significant multivalent effect in recognizing and binding with antigen,which could be applied in improving the sensitivity and accuracy of antibody detection.The development of highly effective vaccine adjuvants is essential for building effective MUC1 glycopeptide based anti-tumor vaccines.An effective adjuvant could not only enhance the immunogenicity of tumor MUC1 glycopeptide antigens,improve the specific immune responses and even prolong the immune surveillance,but also effectively reduce the amount of antigen and reduce side effects.These researches provide new ideas for the design and optimization of MUC1 glycopeptide based cancer vaccines.Meanwhile,the effective adjuvants can be further extended to vaccine development for other diseases.