Synthesis Of α-GalCer Analogues And Evaluation Of The Adjuvanticity Of α-GalCer Coformulated With Rhamnose As Xenoantigen

NKT cells are a unique population of T cells with immunomodulatory properties that link innate and adaptive immune responses.Upon activation,NKT cells rapidly produce a variety of cytokines that enable them to influence immune outcomes.Unlike conventional T cells that interact with peptide/MHC complex,NKT cells recognize lipid antigens presented by CD1d.α-GalCer is the most characteristic agonist of NKT cells,showing good safety and great potential in animal models and clinical trials.However,there are two limitations for α-GalCer to be utilized in clinical immunotherapy:(1)α-GalCer stimulates NKT cells to secrete almost equal amounts of Th1-type and Th2-type cytokines.When these two cytokines are secreted simultaneously,their effects are mutually inhibited.(2)NKT cells’ anergy.High doses of α-GalCer stimulated NKT cells to develop immune disability lasting for several months,and did not respond to subsequent antigen stimulation.This thesis focuses on the above two issues.The first part of this article is designing a new route and synthesize Th2 type iNKT cell agonist OCH.The key steps include three followed steps:olefin metathesis reaction,asymmetric epoxidation reaction and azide ring-opening reaction to epoxy compounds.The advantages of this route include easy access of raw materials;its ability to expand the synthesis of other α-GalCer analogs.The second part of this article is using rhamnose as xenoantigens to increase the adjuvant activity of α-GalCer.Anti-Rha antibodies occur naturally in humans and can bind rhamnose.We envisage embedding rhamnose in a vaccine containing α-GalCer to enhance the ability of α-GalCer to target APCs.Reduce the free state of α-GalCer(prevent or reduce the occurrence of immune anergy),thereby enhancing the adjuvant activity of α-GalCer.Based on previous research of anti-tumor sugar vaccines,we covalently linked the sugar tumor antigen GM3 to α-GalCer to prepare GM3-α-GalCer,and this glycoconjugate can effectively elicit high-titer anti-GM3 IgG antibody.In this paper,we embed the rhamnose component into a liposome vaccine containing GM3-α-GalCer to study whether rhamnose can further improve the anti-GM3 antibody immune response.In view of the involvement of anti-Rha IgM antibodies and IgG antibodies participate in the immune response in different ways.Chapter Ⅲ deals with the use of anti-Rha IgM antibodies and Chapter Ⅳ deals with the use of anti-Rha IgG antibodies.The experimental results showed that pre-immunization of mice triggers the production of anti-Rha IgM antibodies.In the case of low titers,no significant increase in the immune response of the antibodies introduced by GM3-α-GalCer liposomes after rhamnose was introduced.Anti-Rha IgG antibody did not significantly increase the anti-GM3 antibody titer produced by mice induced by GM3-α-GalCer liposome vaccine,and could not alleviate iNKT cells anergy.