Boosting efficacy of oral vaccine candidates by enabling spore display of nitrated antigens

通过硝化抗原的孢子展示来提高口服候选疫苗的功效

• 批准号: 10472983
• 负责人: Aditya Mohan Kunjapur
• 金额: $ 140.63万
• 依托单位: UNIVERSITY OF DELAWARE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-08 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10472983
• 关键词: Amino Acids; Animals; Antibiotic Resistance; Antigens; Attention; Autologous; B-Cell Activation; Bacillus subtilis; Bacteria; Bacterial Antigens; Bacterial Infections; Bacterial Vaccines; Benign; Biological Models; Cells; Consumption; Disease; Educational process of instructing; Exhibits; Exposure to; Helper-Inducer T-Lymphocyte; Immune; Immune response; Immune system; Immunization; Ligands; Light; MHC Class II Genes; Mus; Oral; Organism; Patients; Peptides; Proteins; Recombinants; Reproduction spores; Role; Serotyping; Shigella; Site; Surface; Technology; Temperature; Testing; Vaccination; Vaccines; Virulence; base; delivery vehicle; design; detection platform; immune self tolerance; immunogenic; immunogenicity; insight; microbial; neoantigens; nitration; novel strategies; oral vaccine; pathogen; pathogenic bacteria; polyclonal antibody; preference; prevent; tool; vaccine candidate; vector vaccine

Project Summary Many diseases could be prevented or treated by enlisting the immune system to recognize a specific antigen. Bacterial diseases warrant heightened attention as many bacterial pathogens lack efficacious vaccines and exhibit rising rates of antibiotic resistance. These pathogens often find many ways of evading immune system detection, including varying their most immunogenic antigens. While many virulence-related proteins can be strongly conserved across pathogen serotypes, they often exhibit weak immunogenicity that is insufficient to draw the response of the immune system. In this project, we ask: Are there strategies to shine a light on live bacterial antigens for increased recognition by immune cells? Furthermore, can we couple these strategies to shelf-stable delivery vectors that are simple to administer to patients across the world? We propose a transformational approach to expand the list of candidate antigens for use in live bacterial vaccine vectors by teaching Bacillus subtilis to produce and harness an immunogenic amino acid. This amino acid has been demonstrated to terminate immune self-tolerance when substituted on the surface of autologous proteins in mice. Site-specific introduction of nitrated residues within proteins has resulted in presentation of a neoepitope that is recognized by helper T cells for subsequent activation of B cells that produce polyclonal antibodies. It stands to reason that the immunogenicity of many weakly immunogenic foreign antigens could be increased using this strategy, though this has not yet been tested. One challenge is that prior studies also established a critical but poorly understood role of the MHC Class II locus in enabling immune response to nitrated antigens. Our project will investigate the potential of spore-displayed nitrated antigens as a transformational vaccination platform for bacterial disease, with the Shigella invasion protein antigens as a model system. We will first perform animal studies with Shigella antigens that are weakly immunogenic but strongly conserved across pathogen serotypes to determine if nitration can increase their immunogenicity. To better understand where nitrated residues should be placed for optimal recognition by immune cell machinery, we will develop a high-throughput microbial display platform to screen MHC-II preference towards unnatural peptide ligands. In parallel, we will develop tools to enable site-specific incorporation of the immunogenic amino acid within proteins fused to the spore coat of B. subtilis. Recombinant spores of this non-pathogenic organism can be orally administered and maintain immunization efficacy after exposure to harsh conditions. The spore-based platform has promise to overcome limitations in the manufacture, transport, and administration of vaccines; however, the platform has low immunogenicity. Our strategy to form nitrated residues using this platform could overcome that limitation. From this project, we will gain insights about the requirements for enhanced immunogenicity due to nitration, and we will advance towards a platform technology for immunization that features shelf-stability and oral delivery.

项目概要 许多疾病可以通过免疫系统识别特定抗原来预防或治疗。 由于许多细菌病原体缺乏有效的疫苗和缺乏有效的疫苗，细菌性疾病值得高度关注。 表现出抗生素耐药性不断上升。这些病原体通常会找到多种逃避免疫系统的方法 检测，包括改变其最具免疫原性的抗原。虽然许多毒力相关蛋白可以 在病原体血清型之间高度保守，它们通常表现出弱的免疫原性，不足以 绘制免疫系统的反应。在这个项目中，我们问：是否有策略来照亮现场 细菌抗原以增加免疫细胞的识别？此外，我们能否将这些策略结合起来 易于向世界各地的患者施用的耐贮存的递送载体？ 我们提出了一种变革性方法来扩大用于活细菌疫苗的候选抗原列表 通过教导枯草芽孢杆菌产生和利用免疫原性氨基酸来构建载体。这种氨基酸有 已被证明在自体蛋白质表面取代时可终止免疫自我耐受 在小鼠中。蛋白质内硝化残基的位点特异性引入导致了新表位的呈现 被辅助 T 细胞识别，随后激活产生多克隆抗体的 B 细胞。它 按理说，许多弱免疫原性外来抗原的免疫原性可能会增加 使用此策略，尽管尚未经过测试。一个挑战是先前的研究也建立了 MHC II 类基因座在实现对硝化抗原的免疫反应中发挥着关键但知之甚少的作用。 我们的项目将研究孢子展示硝化抗原作为转化疫苗的潜力 细菌性疾病平台，以志贺氏菌入侵蛋白抗原作为模型系统。我们首先会表演 使用志贺氏菌抗原进行的动物研究，这些抗原具有弱免疫原性，但在病原体中高度保守 血清型以确定硝化是否可以增加其免疫原性。为了更好地了解硝化的位置 残基应放置在免疫细胞机器最佳识别位置，我们将开发一种高通量 微生物展示平台，用于筛选 MHC-II 对非天然肽配体的偏好。与此同时，我们将 开发工具，使免疫原性氨基酸能够在与融合蛋白融合的蛋白质中进行位点特异性整合 枯草芽孢杆菌的孢子衣。这种非病原生物的重组孢子可以口服给药， 暴露于恶劣条件后仍保持免疫效果。基于孢子的平台有望 克服疫苗生产、运输和管理方面的限制；不过该平台有 免疫原性低。我们使用该平台形成硝化残基的策略可以克服这一限制。 从这个项目中，我们将深入了解硝化作用增强免疫原性的要求， 我们将推进具有货架稳定性和口服给药功能的免疫平台技术。