Identification of bactericidal antibody specificities for the development of novel broad-coverage vaccine candidates against Neisseria meningitidis

摘要 脑膜炎奈瑟氏菌（Nm）是一种革兰氏阴性细菌，通常定植于人类咽部 脑膜炎球菌病（IMD）是一种破坏性的疾病， 败血症和脑膜炎。全世界每年报告的IMD病例超过70，000例，并有病例死亡 5%到15%之间。杀菌抗Nm抗体可以预防感染和定殖，并且可以在体内施用。 通过血清杀菌试验（SBA）鉴定，这是体外保护替代物的金标准。 因此，产生保护性杀菌IgG的疫苗接种被认为是一种关键的控制措施 对于IMD。从疫苗抗原的计算机预测开始的“反向疫苗学”方法已经导致 获得许可的基于蛋白质的疫苗，如多组分4CMenB（Bexsero®）。然而，所有持牌反- Nm疫苗的覆盖范围有限，使接种者容易受到非疫苗引起的IMD的影响。 型菌株。迫切需要继续发现能够提供全面覆盖的候选疫苗， 单独或与现有疫苗协同。我们假设下一代的逆转者 疫苗学（“RV 2.0”），其中SBA活性人单克隆抗体（hmAb）由以下产生： 恢复期IMD患者，将为发现针对Nm的疫苗抗原提供平台。团队 教授伦敦帝国理工学院的保罗·兰福德和法迪尔·比德莫斯博士创造了一种新的广泛保护性的 来自康复患者的杀菌hmAb。RV 2.0目前的挑战是识别同源 杀菌hmAb的抗原。Antigen Discovery，Inc. (ADI)加利福尼亚州欧文市建立了泛蛋白质组 微阵列技术用于鉴定与保护性免疫相关的抗体的蛋白质靶标。 用于分析抗体特异性的蛋白质组规模平台以前从未提供给Nm 这项技术有能力迅速推进疫苗的发现， 候选人该项目旨在鉴定杀菌抗体所针对的抗原。奈瑟氏 将开发脑膜炎泛蛋白质组微阵列，用于RV 2.0方法筛选hmAb， 来自儿科IMD患者的恢复期血清，其特征在于具有SBA和其他体外功能性抗体 活性，如补体激活、调理吞噬和粘附抑制。最有前途的 将通过生产和纯化重组蛋白来验证抗原，这些重组蛋白将用于开发 Luminex检测试剂盒用于正向免疫测定的确认。至少5种疫苗候选抗原， 识别不同Nm菌株的抗体在目标群体中具有广泛的免疫原性， 目前包含在任何许可疫苗中的疫苗将在2期SBIR中进行临床前开发 应用程序.这项拨款申请解决了IMD在儿童和成人中的重大问题， 通过鉴定杀菌抗体的蛋白质靶点，为广泛覆盖的疫苗奠定基础。

ABSTRACT Neisseria meningitidis (Nm) is a Gram-negative bacterium that commonly colonizes the human pharyngeal mucosa, but can also cause invasive meningococcal disease (IMD), a devastating disease that presents as septicemia and meningitis. More than 70,000 cases of IMD are reported annually worldwide with case fatality ratios between 5% and 15%. Bactericidal anti-Nm antibodies may prevent infection and colonization and can be identified by the serum bactericidal assay (SBA), which is the gold standard in vitro surrogate of protection. Vaccination that results in protective bactericidal IgG is, therefore, considered a crucial control measure for IMD. A “Reverse Vaccinology” approach that starts with in silico prediction of vaccine antigens has led to licensed protein-based vaccines such as the multicomponent 4CMenB (Bexsero®). However, all licensed anti- Nm vaccines have limited breadth of coverage, leaving vaccinees susceptible to IMD caused by non-vaccine type strains. There is an urgent need for continued discovery of vaccine candidates that will provide full coverage, either individually or in synergy with existing vaccines. We hypothesize that the next generation of Reverse Vaccinology (“RV 2.0”), whereby SBA-active human monoclonal antibodies (hmAbs) are generated from convalescent IMD patients, will provide the platform for discovery of vaccine antigens against Nm. The team of Prof. Paul Langford and Dr. Fadil Bidmos of Imperial College London have generated novel broadly protective bactericidal hmAbs from convalescing patients. The current challenge with RV 2.0 is identifying the cognate antigens of bactericidal hmAbs. Antigen Discovery, Inc. (ADI) of Irvine, CA has established panproteome microarray technology for identification of the protein targets of antibodies associated with protective immunity. A proteome-scale platform for profiling antibody specificity has never before been available to the Nm research community, and this technology has the power to rapidly advance discovery of vaccine candidates. This project aims to identify the antigens targeted by bactericidal antibodies. A Neisseria meningitidis panproteome microarray will be developed for use in an RV 2.0 approach to screen hmAbs and convalescent sera from pediatric IMD patients characterized as having SBA and other in vitro functional antibody activity, such as complement activation, opsonophagocytosis and adhesion inhibition. The most promising antigens will be validated by producing and purifying recombinant proteins, which will be used to develop Luminex assays for confirmation in orthologous immunoassays. At least 5 vaccine candidate antigens that bind antibodies that recognize diverse Nm strains, are broadly immunogenic in the target population and are not currently included in any licensed vaccine will be taken forward for preclinical development in a Phase 2 SBIR application. This grant application addresses the significant problem of IMD in children and adults by laying the foundation for a broad-coverage vaccine through identification of the protein targets of bactericidal antibodies.