Development of the Next Generation of Conjugate Vaccines

项目摘要 第一代结合疫苗在降低发病率和严重程度方面是有效的 由乙型流感嗜血杆菌、肺炎链球菌和脑膜炎奈瑟菌引起的疾病 免疫系统良好的个体体内的细菌。他们在免疫功能低下的患者和老年人身上取得了成功，两人 快速增长的人口，一直非常有限。此外，它们的开发和使用的方法 生产不宜对迅速出现的新致病菌株作出反应。下一代 这些糖靶向疫苗必须引入截然不同的概念才能生产出针对以下病毒的疫苗 新出现的细菌和真菌疾病，多聚糖胶囊是中和的理想靶点 抗体。抗生素耐药菌株的快速筛选使这一需求变得更加迫切。 我们以肺炎链球菌(Sp)为模型系统，开展了这项工作 假设目前的结合抗多糖疫苗的限制因素是低质量的T细胞帮助。 我们最近发表了一种使用Sp的两个原型多糖的新方法的例子。抗多聚糖 抗体具有积累的体细胞突变，精致的特异性和低纳摩尔亲和力 已生成。载脂蛋白和糖链结合结构揭示了糖链结合的独特模式。产品的生产 这些抗体完全依赖于CD4T细胞的帮助和NKT细胞佐剂的存在，并且 保护动物免受微生物挑战。这些结果表明，我们已经开发出一种模块化的 能够驾驭抗多糖反应的系统。推进到临床前研究，并了解 免疫学对多糖的识别我们将开展三个具体目标，拓展我们的发展途径 疫苗基于合成微生物模拟物的概念。目的1：优化抗原和免疫球蛋白 展示平台。单糖到四糖基序可以定义在人类疾病中流行的13种血清型 并包括在获得许可的结合疫苗中。我们将附加所有13个血清型的最小抗原性结构 以增强T细胞识别和依赖性的方式提供给我们的免疫原性平台。抗体 特异性将在葡聚糖微阵列上进行检测。B、T细胞糖链识别的免疫学规律 将会被定义。目的2：高亲和力抗体和T细胞对多糖的分子识别。我们会 用X射线结晶学研究B细胞和T细胞识别多糖的结构规律。这些研究 将为最佳抗原寡糖的设计提供信息。目的3：提高体内安全性和有效性。 我们假设，增强抗蛋白质免疫反应质量的一些相同因素将 也适用于展示多肽的葡聚糖，特别是提高了向淋巴结和 树突状细胞捕获疫苗。这将通过将已知的调色素附着到 粒子发展了微生物模拟的概念。最后，每个优化的平台都将在细菌中进行测试 在老鼠身上挑战。

Project Summary Conjugate vaccines of the first generation have been effective at reducing incidence and severity of diseases caused by Haemophilus influenza B, Streptococcus pneumoniae, and Neisseria meningitides bacteria in individuals with fit immune systems. Their success in immunocompromised patients and elders, two fast growing populations, has been very limited. In addition, the approach used for their development and production is inappropriate to respond to rapidly emerging new pathogenic strains. The next generation of these glycan-targeting vaccines must introduce radically different concepts to produce vaccines against emerging bacterial and fungal diseases for which the glycan capsule is an ideal target for neutralizing antibodies. The fast selection of antibiotic-resistant strains makes this need even more urgent. We embarked on this task using Streptococcus pneumoniae (Sp) as a model system, with the working hypothesis that the limiting factor of current conjugate anti-glycan vaccines was the low quality of T cell help. We recently published examples of a new approach using two prototypical glycans from Sp. Anti-glycan antibodies with an accumulation of somatic mutations, exquisite specificity and low-nanomolar affinities were generated. Apo- and glycan bound structures revealed a unique mode of glycan binding. The production of these antibodies was totally dependent on CD4 T cell help and the presence of an NKT cell adjuvant, and protected animals against microbial challenge. These results suggest that we have developed a modular system capable of harnessing the anti-glycan response. To advance to pre-clinical studies, and understand the immunology of glycan recognition we will carry out three specific aims to expand our approach to develop vaccines based on the concept of synthetic microbial mimics. Aim 1: Optimization of the antigen and display platform. Mono- to tetrasaccharide motifs can define the 13 serotypes that prevail in human diseases and are included in licensed conjugate vaccines. We will attach minimal antigenic structures of all 13 serotypes to our immunogenic platform in ways designed to enhance T cell recognition and dependency. Antibody specificity will be examined on glycan micro-arrays. The immunological rules of B and T cell glycan recognition will be defined. Aim 2: Molecular recognition of glycans by high affinity antibodies and T cells. We will explore the structural rules of glycan recognition by B and T cells using x-ray crystallography. These studies will inform the design of optimal antigenic oligosaccharides. Aim 3: Increasing safety and potency in vivo. We hypothesize that some of the same factors that enhance the quality of anti-protein immune response will also apply to peptide-displayed glycans, particularly improved efficiency of delivery to the lymph node and capture of the vaccine by dendritic cells. This will be tested with the attachment of known opsonins to the particle to develop the concept of microbial mimicry. Finally, each optimized platform will be tested in bacterial challenge in mice.