Elucidating the Structural Requirements for Next-Gen Glycoconjugate Vaccines

阐明下一代糖缀合物疫苗的结构要求 项目摘要 糖缀合物疫苗在全球范围内提供了巨大的健康益处，尽管它们在全球范围内的应用较少。 在某些疾病高危人群中取得了成功。在大多数情况下， 抗原与载体蛋白的相互作用是凭经验进行的，很少关注对抗原与载体蛋白的相互作用至关重要的变量。 免疫反应我们实验室最近的发现为共轭物如何 工作新的模型表明，抗原呈递细胞向T细胞呈递碳水化合物可能 强烈增强抗体反应的效力。该原理在B组小鼠模型中的应用 链球菌病和土拉热弗朗西丝氏菌感染， 导致疫苗比标准糖缀合物疫苗更具保护性。我们还展示了 肽接头和缀合位点在增强缀合效率和缀合活性方面的关键作用 对疫苗的免疫反应。这些结果支持肽糖缀合物疫苗提供 对细菌挑战的上级保护。值得注意的是，使用肽而不是蛋白质作为免疫调节剂， 载体在低得多的碳水化合物特异性IgG水平下提供更好的保护。该观察结果 挑战了由糖缀合物诱导的IgG的量与由糖缀合物诱导的IgG的量之间的直接相关性的范例。 保护蛋白质vs肽产生的抗体和免疫细胞的综合评价 糖缀合物将阐明使肽疫苗极其有效的特征。我们将评估 在IgG亚型、亲和力、亲合力和功能活性方面对糖肽疫苗的抗体应答， 以及阐明记忆B细胞上表达的共刺激/共抑制分子， 这与所制备的抗体的功能有关。这种方法将定义使 糖肽诱导的抗体如此有效，并形成了筛选B细胞杂交瘤产生的基础 从肽和蛋白质糖缀合物。高功能抗体与临界B细胞的相关性 生物标志物将被识别。产生具有不同程度保护活性的抗体的杂交瘤 将通过BCR测序进行评价。低和高效抗体的Fab片段将被共- 用GBSIII寡糖结晶以研究表位特异性在保护中的作用。我们将 应用我们对这些肽/多糖结合物的研究， 糖缀合物疫苗的免疫力。! !

Elucidating the Structural Requirements for Next-Gen Glycoconjugate Vaccines Project Summary Glycoconjugate vaccines provide enormous health benefits globally, although they have been less successful in some populations at high risk for developing disease. In most cases, conjugation of the sugar antigen to the carrier protein has been done empirically with little attention on variables critical for the immune response. Recent findings from our lab offer a new and rational explanation for how conjugates work. The new model suggests that carbohydrate presentation to T cells by antigen-presenting cells may strongly enhance the efficacy of antibody responses. Application of this principle in mouse models of group B streptococcal disease and Francisella tularensis infection by using a carrier peptide rather than a protein, resulted in vaccines more protective than standard glycoconjugate vaccines. We have also demonstrated the critical role of the peptide linker and the conjugation site in enhancing both the conjugation efficiency and the immune response to vaccines. The results support the notion that peptide glycoconjugate vaccines provide superior protection against bacterial challenges. Remarkably, the use of a peptide instead of a protein as a carrier confers better protection at much lower levels of carbohydrate specific IgG. This observation challenges the paradigm of a direct correlation between the amount of IgG induced by a glycoconjugate and protection. A comprehensive evaluation of antibodies and immune cells generated by protein vs peptide glycoconjugates will clarify the features that make peptide vaccines extremely potent. We will evaluate the antibody response to glycopeptide vaccines in terms of IgG subtypes, affinity, avidity and functional activity, as well as, elucidate the costimulatory/coinhibitory molecules being expressed on memory B cells and relate this to the functionality of the antibodies being made. This approach will define the characteristics that make glycopeptide-induced antibodies so potent and forms the basis for screening of B-cell hybridomas produced from peptide vs protein glycoconjugates. Correlates of highly functional antibody and critical B cell biomarkers will be identified. Hybridomas that produce antibodies with different degrees of protective activity will be evaluated by BCR sequencing. Fab fragments of low and highly effective antibodies will be co- crystallized with GBSIII oligosaccharide to investigate the role of epitope specificity in protection. We will apply our studies of these peptide/polysaccharide conjugates to create more efficacious and longer lasting immunity to glycoconjugate vaccines. ! !