Synthesis And Study Of Hetero-Glycoadjuvant@AuNPs For Enhanced T Cell Responses

Immunotherapy is a novel antitumor approach which utilizes our own immune system to kill tumor cells.It has attracted wide attention recently due to eutherapeutic effect,quick responses and low tumor metastasis.Immune adjuvant plays a critical role in immunotherapy as a kind of helper component that can significantly improve the immune activities of antigens and enhance T cell responses.In fact,internalization and retention of antigen and adjuvants in lymph node are directly related to therapeutical efficacy in vivo.Some works indicate specific binding between C-type lectin receptors(CLRs)and carbohydrate ligands on surface of antigen-presenting cells(APCs)is important not only for the induction of T-cell responses,but also for the inhibition of immunosuppressive microenvironment.In this contribution,the hetero-glycopolymer containing two types of glycan and catechol groups was synthesized by controlled radical polymerization(CRP)and click-chemistry.Then catechol group was utilized to reduce HAuCl4and to react with amino-functionalized CpG(cytosine-phosphate-guanine oligodeoxyribonucleotide)at the same time.Finally,we successfully fabricated multifunctional hetero-glycoadjuvant@AuNPs(CpG-GM@AuNPs)containing glucose and mannose units.A series of experiments in vivo and vitro were carried out to characterize biological performances of glycoadjuvant.The following is main content of this paper,which is divided into two parts:(1)One-pot,multicomponent strategy for designing hetero-glycoadjuvant@AuNPs First,poly(propynyl methacrylate)(PPgMA)was obtained by photo-induced reversible addition-fragmentation chain transfer(RAFT)polymerization using propynyl methacrylate(PgMA)as monomer.Then mannose units were modified to side chain of PPgMA by alkynyl-azide click reaction to prepare mannose-containing polymer(PMAM).Then hetero-glycopolymer containing two kinds of sugar and catechol groups,was fabricated by chain extension experiment with PMAM as macro-RAFT,N-3,4-dihydroxybenzenethyl methacrylamide(DMA)and 2-(methacrylamido)glucopyranose(MAG)as monomers.Finally,reduction of HAuCl4 and conjugation of amine-terminal CpG(CpG-NH2)could react in a single step to form hetero-glycoadjuvant@AuNPs in one-pot.The experimental results showed that one-pot multicomponent strategy effectively conjugated CpG,glucose and mannose units to obtain spheric hetero-glycoadjuvant@AuNPs.(2)The biological properties of hetero-glycoadjuvant@AuNPs.By means of cell surface staining,cell uptake test,cytotoxicity test,adjuvant activity test and cellular immunity,compared with homo-glycoadjuvant@AuNPs,we found that hetero-glycoadjuvant@AuNPs could greatly promote APCs maturation and potentiate antigen-specifc CD8+ T-cell responses in subcutaneous B16OVA model.