Development of the Next Generation of Conjugate Vaccines

项目概要 第一代结合疫苗可有效降低疾病的发生率和严重程度 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 具有健康免疫系统的个体中的细菌。他们在免疫功能低下的患者和老年人中取得了成功，两个 人口快速增长，数量已经非常有限。此外，用于其开发的方法和 生产不适合应对迅速出现的新致病菌株。下一代 这些聚糖靶向疫苗必须引入完全不同的概念来生产针对 新出现的细菌和真菌疾病，聚糖胶囊是中和的理想目标 抗体。抗生素抗性菌株的快速选择使得这一需求变得更加紧迫。 我们使用肺炎链球菌 (Sp) 作为模型系统开始这项任务， 假设当前抗聚糖结合疫苗的限制因素是 T 细胞帮助的质量低。 我们最近发表了使用来自 Sp 的两种原型聚糖的新方法的示例。抗聚糖 具有体细胞突变积累、精细特异性和低纳摩尔亲和力的抗体 生成的。 Apo 和聚糖结合结构揭示了独特的聚糖结合模式。生产 这些抗体完全依赖于 CD4 T 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了一个模块化的 能够利用抗聚糖反应的系统。推进临床前研究，并了解 聚糖识别的免疫学我们将实现三个具体目标来扩展我们的开发方法 基于合成微生物模拟概念的疫苗。目标1：优化抗原和 展示平台。单糖到四糖基序可以定义人类疾病中流行的 13 种血清型 并包含在获得许可的结合疫苗中。我们将附上所有 13 种血清型的最小抗原结构 以旨在增强 T 细胞识别和依赖性的方式加入我们的免疫原性平台。抗体 将在聚糖微阵列上检查特异性。 B和T细胞聚糖识别的免疫学规则 将被定义。目标 2：高亲和力抗体和 T 细胞对聚糖的分子识别。我们会 使用 X 射线晶体学探索 B 细胞和 T 细胞识别聚糖的结构规则。这些研究 将为最佳抗原寡糖的设计提供信息。目标 3：提高体内安全性和效力。 我们假设一些增强抗蛋白免疫反应质量的相同因素将 也适用于肽展示聚糖，特别是提高了递送至淋巴结的效率 树突状细胞捕获疫苗。这将通过将已知的调理素附着到 粒子发展了微生物拟态的概念。最后，每个优化平台都将在细菌中进行测试 对小鼠的挑战。

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.