Polyfluorophenyl Ester-terminated Homobifunctional Cross-linker For Preparation Of Protein Conjugates And Immunological Properties Of Carbohydrate-Based Anti-cancer Vaccines

The dissertation consists of two parts.The first part describes the preparation of protein conjugates with active ester.The second part studies the antibody immune response of vaccines targeting tumor-associated carbohydrate antigens(TACAs)and explores the impact of the covalent linker between natural killer T(NKT)cell agonist and TACAs on the efficacy of vaccines.N-hydroxysuccinimide ester is widely used in protein conjugation.It has high reactivity,but it has not enough stability.However,p-nitrophenyl ester possesses high stability,it has low reactivity.An active ester that has the improved balance between reactivity and stability would be desirable with high incorporation efficiencies.In the dissertation,the reactivities of five active esters(N-hydroxysuccinimide ester,p-nitrophenyl ester,phenylseleno ester,tetra-and penta-fluorophenyl esters)were compared by reacting with phenethylamine at three different pH conditions.Then the corresponding adpic acid diester linker were prepared to conjugate proteins with the small functional molecules.In contrast to N-hydroxysuccinimide ester and p-nitrophenyl ester,phenylseleno ester,tetra-and penta-fluorophenyl esters showed an improved balance between reactivity and stability,giving rise to the protein conjugates with good incorporation efficiency.The abnormal glycans express excessively on the surface of tumor cells.However,due to T-cell independence,carbohydrates are not able to inducing antibody class switching from IgM to IgG.Our group reported a fully synthetic cancer vaccine candidate STn-aGalCer.The vaccines were able to rapidly produce high titer of IgG.Therefore,to explores the impact of the covalent linker between natural killer T cell agonist and TACAs,the antibody immune responses of covalently conjugate vaccine(STn-aGalCer)and non-covalent conjugate vaccine(STn-?GalCer/aGalCer)were compared.The results showed that the anti-STn IgG antibody titer induced by STn-pGalCer/aGalCer is comparable to that of STn-aGalCer.