A Fully Synthetic Carbohydrate-based Cancer Vaccine

描述(申请人提供)：Globo-H、Lewis、TN和STN等寡糖的过度表达是致癌转化细胞的共同特征。利用这种异常糖基化来开发癌症疫苗的努力由于难以诱导针对肿瘤相关碳水化合物与载体蛋白的经典偶联的高滴度的免疫球蛋白抗体而变得复杂。我们已经设计、化学合成和免疫学评估了一些完全合成的候选疫苗，以建立克服肿瘤相关碳水化合物和糖肽免疫原性差的策略。我们已经发现，由TLR2激动剂、混杂多肽T辅助表位和肿瘤相关糖肽组成的三组分疫苗可以在小鼠体内诱导出异常高滴度的能够识别表达肿瘤相关碳水化合物的癌细胞的抗体。候选疫苗的优异特性归因于局部产生细胞因子，上调共刺激蛋白，增强巨噬细胞和树突状细胞的摄取，以及避免表位抑制。竞争性更新的一个重要目标是通过检查各种内置佐剂、使用外来的和MUC1衍生的辅助T表位以及使用日益复杂的碳水化合物来进一步开发全合成多组分候选疫苗。我们的中心假设是，这些参数关键地调节体液和细胞免疫反应，只有通过详细的结构-活性关系研究才能优化。此外，通过研究糖基化对MHC-I和MHC-II细胞内糖肽运输、加工和递呈的影响，我们希望建立基于多组分(Glyco)肽的疫苗的一般设计原则。在拟议的研究完成后，我们希望为I/II期临床试验奠定坚实的基础。我们还将使用多组分免疫原技术来产生针对不同糖型MUC1的糖肽特异性单抗(MAb)，我们希望利用这些单抗来确定肿瘤组织表达的糖型。在这方面，目前还缺乏针对MUC1重要表位的糖肽特异性单抗。然而，这种试剂是未来个性化免疫治疗所需要的，在这种治疗中，多组分癌症疫苗的糖部分的结构是根据癌症组织的糖表达而定制的。此外，明确定义的单抗也是基础癌症研究所必需的，例如，在用于疫苗评估的动物模型中评估碳水化合物的表达时也需要这样的单抗。最后，我们将开发一套无铜点击试剂，用于癌症标记物的发现和合成抗原的加工研究。 公共卫生相关性：肿瘤进展与细胞表面出现不寻常的碳水化合物密切相关。虽然人们已经意识到这种异常表达可以被用于癌症疫苗设计，但基于碳水化合物的癌症疫苗的开发因在大多数患者中激发强大的免疫反应而变得复杂。我们正在开发全合成多组分候选疫苗，可以克服肿瘤相关碳水化合物免疫原性差的问题，并为癌症免疫治疗提供了前景。

DESCRIPTION (provided by applicant): The over-expression of oligosaccharides such as Globo-H, LewisY, Tn and STn is a common feature of oncogenic transformed cells. Endeavors to exploit this aberrant glycosylation for cancer vaccine development has been complicated by difficulties of eliciting high titers of IgG antibodies against classical conjugates of tumor-associated carbohydrates to carrier proteins. We have designed, chemical synthesized and immunologically evaluated a number of fully synthetic vaccine candidates to establish strategies to overcome the poor immunogenicity of tumor-associated carbohydrates and glycopeptides. We have found that a three-component vaccine composed of a TLR2 agonist, a promiscuous peptide T-helper epitope and a tumor-associated glycopeptides, can elicit in mice exceptionally high titers of IgG antibodies that can recognize cancer cells expressing the tumor-associated carbohydrate. The superior properties of the vaccine candidate are attributed to the local production of cytokines, upregulation of co-stimulatory proteins, enhanced uptake by macrophages and dendritic cells, and avoidance of epitope suppression. An important aim of the competitive renewal is to further develop the fully synthetic multi-component vaccine candidates by examining various in-build adjuvants, employ foreign and MUC1-derived helper T- epitopes and use carbohydrates of increasing complexity. Our central hypothesis is that these parameters critically modulate humoral and cellular immune responses and can only be optimized by detailed structure- activity relationship studies. Furthermore, by examining the influence of glycosylation on intracellular trafficking, processing and presentation of (glyco)peptides by MHC-I and MHC-II we hope to establish general design principles for multi-component (glyco)peptide-based vaccines. At the completion of the proposed studies we expected to have laid a firm foundation for a phase I/II clinical trial. We will also employ the multi-component immunogen technology for generating glycopeptide-specific monoclonal antibodies (MAbs) for various glycoforms of MUC1, which we expect to utilize to determine glycoforms expressed by tumor tissue. In this respect, there is a lack of well-characterized glycopeptide- specific MAbs for important epitopes of MUC1. Such reagents are, however, required for future personalized immuno-therapy in which the structure of the saccharide moiety of a multi-component cancer vaccine is tailored to the saccharide expression by cancerous tissue. Furthermore, well-defined MAbs are also required for basic cancer research and, for example, are needed for evaluation of carbohydrate expression in an animal model for vaccine evaluation. Finally, we will develop a suite of Cu-free click reagents for cancer marker discovery and studying processing of synthetic antigens. PUBLIC HEALTH RELEVANCE: Tumor progression is intimately associated with the appearance of unusual carbohydrates on the surface of cells. Although it has been realized that this abnormal expression can be exploited for cancer vaccine design, carbohydrate-based cancer vaccine development has been complicated by the difficulty of eliciting robust immune responses in most patients. We are developing fully synthetic multi-component vaccine candidates that can overcome the poor immunogenicity of tumor-associated carbohydrates and offer a prospect for use in cancer immune therapy.