Pifferi Carlo, Aguinagalde Leire, Ruiz-de-Angulo Ane, Sacristán Nagore, Baschirotto Priscila Tonon, Poveda Ana, Jiménez-Barbero Jesús, Anguita Juan, Fernández-Tejada Alberto
Chemical Immunology Laboratory, Center for Cooperative Research in Biosciences (CIC BioGUNE), Basque Research and Technology Alliance (BRTA) Biscay Technology Park, Building 801A 48160 Derio Spain
Chemical Glycobiology Laboratory, CIC BioGUNE, BRTA Spain.
Chem Sci. 2023 Mar 1;14(13):3501-3513. doi: 10.1039/d2sc05639a. eCollection 2023 Mar 29.
The overexpression of aberrantly glycosylated tumor-associated mucin-1 (TA-MUC1) in human cancers makes it a major target for the development of anticancer vaccines derived from synthetic MUC1-(glyco)peptide antigens. However, glycopeptide-based subunit vaccines are weakly immunogenic, requiring adjuvants and/or additional immunopotentiating approaches to generate optimal immune responses. Among these strategies, unimolecular self-adjuvanting vaccine constructs that do not need coadministration of adjuvants or conjugation to carrier proteins emerge as a promising but still underexploited approach. Herein, we report the design, synthesis, immune-evaluation in mice, and NMR studies of new, self-adjuvanting and self-assembling vaccines based on our QS-21-derived minimal adjuvant platform covalently linked to TA-MUC1-(glyco)peptide antigens and a peptide helper T-cell epitope. We have developed a modular, chemoselective strategy that harnesses two distal attachment points on the saponin adjuvant to conjugate the respective components in unprotected form and high yields orthogonal ligations. In mice, only tri-component candidates but not unconjugated or di-component combinations induced significant TA-MUC1-specific IgG antibodies able to recognize the TA-MUC1 on cancer cells. NMR studies revealed the formation of self-assembled aggregates, in which the more hydrophilic TA-MUC1 moiety gets exposed to the solvent, favoring B-cell recognition. While dilution of the di-component saponin-(Tn)MUC1 constructs resulted in partial aggregate disruption, this was not observed for the more stably-organized tri-component candidates. This higher structural stability in solution correlates with their increased immunogenicity and suggests a longer half-life of the construct in physiological media, which together with the enhanced antigen multivalent presentation enabled by the particulate self-assembly, points to this self-adjuvanting tri-component vaccine as a promising synthetic candidate for further development.
异常糖基化的肿瘤相关粘蛋白1（TA-MUC1）在人类癌症中的过表达使其成为基于合成MUC1-（糖）肽抗原的抗癌疫苗开发的主要靶点。然而，基于糖肽的亚单位疫苗免疫原性较弱，需要佐剂和/或额外的免疫增强方法来产生最佳免疫反应。在这些策略中，不需要共施用佐剂或与载体蛋白偶联的单分子自佐剂疫苗构建体是一种有前景但仍未充分利用的方法。在此，我们报告了基于我们的QS-21衍生的最小佐剂平台与TA-MUC1-（糖）肽抗原和肽辅助性T细胞表位共价连接的新型自佐剂和自组装疫苗的设计、合成、小鼠免疫评估及核磁共振研究。我们开发了一种模块化的化学选择性策略，该策略利用皂苷佐剂上的两个远端连接点以未保护的形式和高产率通过正交连接偶联各自的组分。在小鼠中，只有三组分候选物而非未偶联的或双组分组合诱导出能够识别癌细胞上TA-MUC1的显著的TA-MUC1特异性IgG抗体。核磁共振研究揭示了自组装聚集体的形成，其中亲水性更强的TA-MUC1部分暴露于溶剂中，有利于B细胞识别。虽然双组分皂苷-（Tn）MUC1构建体的稀释导致部分聚集体破坏，但对于组织更稳定的三组分候选物未观察到这种情况。溶液中这种更高的结构稳定性与其增强的免疫原性相关，并表明该构建体在生理介质中的半衰期更长，这与颗粒自组装实现的增强的抗原多价呈递一起，表明这种自佐剂三组分疫苗是一种有前景的用于进一步开发的合成候选物。
