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）：脑膜炎的奈瑟氏菌在撒哈拉以南非洲引起爆炸性流行病。大多数是由囊膜组菌株引起的。但是，W-135和X菌株也会在该区域引起流行病，并且一旦引入了A组A多糖蛋白蛋白结合疫苗，这些菌株可能会出现。我们的目标是为非洲开发脑膜炎球菌疫苗，该疫苗针对所有囊群的菌株。我们的方法是使用针对“ B组疫苗”鉴定的新型蛋白质抗原，该抗原还会引起针对其他胶囊菌株的保护性抗体。这些“非常规”的抗原将以具有强大天然佐剂的简单外膜囊泡（OMV）表示。我们的研究将基于先前使用清洁剂提取的OMV疫苗的经验，事实证明，这些疫苗在人类中是安全有效的。他们的主要局限性是它们引起主要针对Pora的血清杀菌抗体，该抗体是抗原可变的。为了扩展具有异源Pora菌株的保护，我们制备了B组菌株的突变体，这些突变体设计为过表达因子H结合蛋白（FHBP），这是两种有希望的B组重组蛋白疫苗中的一种新型抗原。通过引入LPS生物合成中的额外突变，我们减弱了内毒素活性。在小鼠中，由突变体制备的非剂量处理的OMV疫苗引起了针对遗传多样的B菌株的血清杀菌抗体反应，以及从非洲的流行病组A，W-135和X菌株。我们的假设是，由非洲突变菌株制备的天然OMV疫苗将引起针对PORA，FHBP和其他由非洲菌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清洁剂提取的需求，OMV用于降低常规OMV疫苗中的LPS，但也提取了所需的抗原（例如FHBP）。在AIM 1中，我们将研究编码来自非洲菌株的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AIM 2中，我们将通过定量捕获ELISA测量抗原表达，以及通过流式细胞仪对活细菌的抗原表面访问。在AIM 3中，我们将创建最近的非洲流行病的突变体，该突变体将设计为表达多个Pora分子，过表达FHBP并减弱内毒素。还将选择疫苗菌株以自然高表达粘附蛋白/invasin，NADA。我们将从突变体中制备天然OMV疫苗，并通过测量与疫苗在体外孵育的人PBMC的炎症细胞因子反应来评估OMV毒性。我们将对小鼠和婴儿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。结果将提供原则的证明，即OMV疫苗在人类中可能会耐受性良好并引起广泛的保护性免疫。这些发现将支持人类中OMV疫苗测试的应用，以控制由所有囊群菌株引起的萨哈拉以下脑膜炎球菌流行病的控制。 公共卫生相关性：脑膜炎球菌在非洲以下引起脑膜炎的爆炸性流行病，几个月内可能涉及100,000多个病例。大多数流行病是由封装的A组菌株引起的，但其他囊群的菌株也开始引起该地区的流行病。针对非洲正在开发针对A组疾病的多糖共轭疫苗，但人们严重担心，一旦引入了与该组的A组群体免疫，与其他胶囊的菌株可能会出现并引起流行病。我们建议从突变体脑膜炎球菌菌株中开发出一种外膜囊泡疫苗，该疫苗设计用于过度表达有希望的蛋白质疫苗抗原，这是一种普遍的脑膜炎球菌疫苗，用于非洲，针对所有囊肿组的菌株引起的疾病。