An engineered meningococcal OMV vaccine for Africa against all capsular groups

针对非洲所有荚膜群的工程脑膜炎球菌 OMV 疫苗

• 批准号: 8007423
• 负责人: Dan M. Granoff
• 金额: $ 47.78万
• 依托单位: CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8007423
• 关键词: Address; Adjuvant; Africa; Africa South of the Sahara; African; Age; Amino Acid Sequence; Anabolism; Antibodies; Antibody Formation; Antigen Targeting; Antigenic Variation; Antigens; Attenuated; Bacteria; Bacterial Adhesins; Binding Proteins; Cells; Child; Collection; Complement; Complement Factor H; Conjugate Vaccines; Cytolysis; Data; Detergents; Developed Countries; Development; Disease; Dose; Encapsulated; Endemic Diseases; Endotoxins; Engineering; Enzyme-Linked Immunosorbent Assay; Epidemic; Flow Cytometry; Genes; Genetic; Genotype; Goals; Human; Immune; Immune Sera; Immunity; Immunization Schedule; Immunoglobulin Variable Region; Immunologic Memory; In Vitro; Incidence; Incubated; Infant; Inflammatory Response Pathway; Institutes; Iron; Laboratories; Licensing; Life; Mass Immunization; Measures; Mediating; Membrane; Membrane Proteins; Meningitis; Meningococcal vaccine; Methods; Monoclonal Antibodies; Mus; Mutation; Neisseria meningitidis; Pathway interactions; Patients; Peripheral Blood Mononuclear Cell; Persons; Phenotype; Polysaccharides; Preparation; Prevalence; Prevention; Prevention strategy; Primates; Proteins; Public Health; Recombinant Proteins; Relative (related person); Research; Safety; Sahara; Sampling; Serological; Serum; Surface; Surface Antigens; Testing; Toxic effect; Vaccine Antigen; Vaccine Design; Vaccines; Variant; Vesicle; Western Blotting; age group; bactericide; base; capsule; disorder prevention; experience; genome sequencing; high risk; immunogenicity; major outer membrane protein; mutant; novel; public health relevance; response; vaccine candidate; vaccine efficacy

DESCRIPTION (provided by applicant): Neisseria meningitidis causes explosive epidemics in sub-Saharan Africa. Most are caused by capsular group A strains. However, group W-135 and X strains also cause epidemics in this region, and these strains may emerge once mass immunization with a group A polysaccharide-protein conjugate vaccine is introduced. Our goal is to develop a meningococcal vaccine for Africa that targets strains from all capsular groups. Our approach will be to use novel protein antigens identified for "group B vaccines", which also elicit protective antibodies against strains with other capsules. These "unconventional" antigens will be presented in simple outer membrane vesicles (OMV) that have potent natural adjuvants. Our studies will build on previous experience with detergent-extracted OMV vaccines, which are proven to be safe and effective in humans. Their major limitation is that they elicit serum bactericidal antibodies primarily directed at PorA, which is antigenically variable. To extend protection to strains with heterologous PorA, we prepared mutants of group B strains that were engineered to over-express factor H binding protein (fHbp), which is a novel antigen in two promising group B recombinant protein vaccines. By introducing an additional mutation in LPS biosynthesis, we attenuated endotoxin activity. In mice, non-detergent-treated OMV vaccines prepared from the mutants elicited serum bactericidal antibody responses against genetically diverse group B strains, as well as epidemic group A, W-135 and X strains from Africa. Our hypothesis is that a native OMV vaccine prepared from mutant strains from Africa will elicit even broader bactericidal antibodies directed at PorA, fHbp and other antigens expressed by strains from Africa. Further, the LPS mutation will eliminate the need for detergent extraction of the OMV, which is used to decrease LPS in conventional OMV vaccines, but also extracts desirable antigens such as fHbp. In Aim 1, we will investigate genetic lineages and sequence diversity of genes encoding fHbp, PorA and other vaccine antigens among 200 meningococcal isolates from a geographically diverse collection of strains from Africa. In Aim 2, we will measure antigen expression by a quantitative capture ELISA, and antigen surface-accessibility on live bacteria by flow cytometry. In Aim 3, we will create mutants of recent African epidemic strains, which will be engineered to express more than one PorA molecule, over-express fHbp, and have attenuated endotoxin. The vaccine strains also will be selected for naturally high expression of an adhesin/invasin, NadA. We will prepare native OMV vaccines from the mutants, and assess OMV toxicity by measuring inflammatory cytokine responses of human PBMCs incubated in vitro with the vaccine. We will immunize mice and infant primates and measure serum bactericidal antibody responses against strains from Africa. The results will provide proof of principle that the OMV vaccine is likely to be well-tolerated in humans and elicit broad protective immunity. These findings would support an application to test the OMV vaccine in humans for control of meningococcal epidemics in sub-Sahara caused by strains from all capsular groups. PUBLIC HEALTH RELEVANCE: Meningococci cause explosive epidemics of meningitis in sub-Sahara Africa that can involve more than 100,000 cases in a few months. Most epidemics have been caused by encapsulated group A strains but strains from other capsular groups also have begun to cause epidemics in the region. A polysaccharide conjugate vaccine against group A disease is being developed for Africa but there is grave concern that strains with other capsules may emerge and cause epidemics once mass immunization with the group A conjugate vaccine is introduced. We propose to develop an outer membrane vesicle vaccine from mutant meningococcal strains, engineered for over-expression of promising protein vaccine antigens, as a universal meningococcal vaccine for Africa against disease caused by strains from all capsular groups.

描述（由申请人提供）：脑膜炎奈瑟菌在撒哈拉以南非洲地区引起爆炸性流行。大多数是由 A 组荚膜菌株引起的。然而，W-135和X组毒株也在该地区引起流行，一旦采用A组多糖-蛋白结合疫苗进行大规模免疫，这些毒株可能会出现。我们的目标是为非洲开发一种针对所有荚膜菌群菌株的脑膜炎球菌疫苗。我们的方法将是使用为“B 组疫苗”鉴定的新型蛋白质抗原，该抗原也能通过其他胶囊引发针对菌株的保护性抗体。这些“非常规”抗原将呈现在具有有效天然佐剂的简单外膜囊泡（OMV）中。我们的研究将建立在以前使用洗涤剂提取的 OMV 疫苗的经验基础上，这些疫苗已被证明对人类安全有效。它们的主要局限性是它们会引发主要针对 PorA 的血清杀菌抗体，而 PorA 的抗原性是可变的。为了扩大对具有异源 PorA 的菌株的保护，我们制备了 B 组菌株的突变体，这些突变体被设计为过表达 H 因子结合蛋白 (fHbp)，这是两种有前途的 B 组重组蛋白疫苗中的一种新抗原。通过在 LPS 生物合成中引入额外的突变，我们减弱了内毒素活性。在小鼠中，由突变体制备的未经洗涤剂处理的 OMV 疫苗引发了针对遗传多样性 B 组菌株以及来自非洲的流行 A 组、W-135 和 X 组菌株的血清杀菌抗体反应。我们的假设是，由非洲突变毒株制备的天然 OMV 疫苗将引发针对 PorA、fHbp 和非洲毒株表达的其他抗原的更广泛的杀菌抗体。此外，LPS 突变将消除对 OMV 去污剂提取的需要，这种去污剂提取用于减少传统 OMV 疫苗中的 LPS，但也可以提取所需的抗原，例如 fHbp。在目标 1 中，我们将研究来自非洲不同地理菌株集合的 200 种脑膜炎球菌分离株中编码 fHbp、PorA 和其他疫苗抗原的基因的遗传谱系和序列多样性。在目标 2 中，我们将通过定量捕获 ELISA 测量抗原表达，并通过流式细胞术测量活细菌上抗原表面的可及性。在目标 3 中，我们将创建最近非洲流行毒株的突变体，这些突变体将被设计为表达多个 PorA 分子、过度表达 fHbp 并减弱内毒素。还将选择天然高表达粘附素/侵袭素 NadA 的疫苗株。我们将从突变体中制备天然 OMV 疫苗，并通过测量与疫苗体外孵育的人 PBMC 的炎症细胞因子反应来评估 OMV 毒性。我们将对小鼠和幼年灵长类动物进行免疫，并测量针对非洲菌株的血清杀菌抗体反应。结果将提供原理证明，证明 OMV 疫苗可能在人类中具有良好的耐受性并引发广泛的保护性免疫力。这些发现将支持在人类中测试 OMV 疫苗的应用，以控制撒哈拉以南地区由所有荚膜群菌株引起的脑膜炎球菌流行。 公共卫生相关性：脑膜炎球菌在撒哈拉以南非洲地区引起脑膜炎的爆炸性流行，几个月内可能涉及超过 100,000 例病例。大多数流行病是由 A 组荚膜菌株引起的，但其他荚膜组的菌株也已开始在该地区引起流行病。非洲正在开发一种针对 A 组疾病的多糖结合疫苗，但人们非常担心，一旦采用 A 组结合疫苗进行大规模免疫，可能会出现带有其他胶囊的菌株并引起流行病。我们建议利用突变型脑膜炎球菌菌株开发一种外膜囊泡疫苗，该疫苗经过改造可过度表达有希望的蛋白质疫苗抗原，作为非洲针对所有荚膜组菌株引起的疾病的通用脑膜炎球菌疫苗。