Neisseria meningitidis antigens expressed in infection

感染中表达的脑膜炎奈瑟菌抗原

• 批准号: 6815114
• 负责人: Dan M. Granoff
• 金额: $ 20.01万
• 依托单位: CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6815114
• 关键词: Neisseria meningitidis; antigen antibody reaction; bacterial antigens; bacterial genetics; bacterial meningitis; bacterial proteins; biological models; clinical research; disease /disorder model; disease /disorder prevention /control; enzyme linked immunosorbent assay; flow cytometry; gene expression; gene expression profiling; gram negative bacteria; human subject; infant animal; laboratory mouse; laboratory rat; microorganism culture; pathologic process; patient oriented research; protein purification; recombinant proteins; septicemia; vaccine development

DESCRIPTION (provided by applicant): N. meningitidis is an important cause of meningitis and sepsis. Conventional approaches to develop a vaccine for prevention of disease caused by capsular group B strains, which account for 30-80% of all cases, have been largely unsuccessful, and therefore there is a need for the identification of new vaccine candidates. To date, all candidate antigens have been identified using organisms grown in artificial media or on epithelial or endothelial cell monolayers. Little is known, however, about the gene expression profile of N. meningitidis during infection in vivo. Our hypothesis is that N. meningitidis grown in the infant rat model of bacteremia or in human whole blood will show specific genes that are up-regulated or activated compared to those expressed in artificial culture. Furthermore, genes that are up-regulated during invasive infection that encode novel proteins that are conserved in N. meningitidis, and that are predicted to be surface-accessible, will be promising vaccine candidates. We propose to use quantitative real-time PCR to study the temporal gene expression profile of N. meningitidis isolated from the bloodstream of infected infant rats and from the human blood infection model at different time-points, and also to compare the respective expression profiles with those of bacteria grown in broth. We will evaluate the immunogenicity of the recombinant proteins as purified His-tagged or GST-fusion proteins, and as "native" proteins in E. coli outer membrane vesicles. Antisera from immunized mice will be analyzed by ELISA, FACS, serum bactericidal activity, and passive protection in the infant rat model. The proposed studies may identify new antigens capable of eliciting broadly protective antibody for prevention of N. meningitidis disease, including group B strains for which there is currently no vaccine available. Also, characterization of gene expression in an in vivo model will lead to a better understanding of meningococcal pathogenesis.

描述（由申请人提供）：脑膜炎奈瑟菌是脑膜炎和败血症的重要原因。开发疫苗来预防由荚膜 B 组菌株引起的疾病（占所有病例的 30-80%）的疫苗基本上不成功，因此需要鉴定新的候选疫苗。迄今为止，所有候选抗原均已使用在人工培养基中或上皮或内皮细胞单层上生长的生物体进行了鉴定。然而，人们对脑膜炎奈瑟氏菌在体内感染过程中的基因表达谱知之甚少。我们的假设是，在菌血症幼鼠模型或人全血中生长的脑膜炎奈瑟氏球菌将显示出与人工培养物中表达的基因相比上调或激活的特定基因。此外，在侵袭性感染期间上调的基因编码脑膜炎奈瑟氏球菌中保守的新型蛋白质，并且预计可通过表面接触，将成为有希望的候选疫苗。我们建议使用定量实时PCR来研究从受感染的幼鼠血流和人类血液感染模型中分离的脑膜炎奈瑟氏菌在不同时间点的时间基因表达谱，并将各自的表达谱与肉汤中生长的细菌的表达谱进行比较。我们将评估重组蛋白作为纯化的 His 标签或 GST 融合蛋白以及作为大肠杆菌外膜囊泡中的“天然”蛋白的免疫原性。将通过 ELISA、FACS、血清杀菌活性和幼鼠模型中的被动保护来分析来自免疫小鼠的抗血清。拟议的研究可能会鉴定出能够引发广泛保护性抗体以预防脑膜炎奈瑟氏球菌疾病的新抗原，包括目前尚无疫苗可用的 B 组菌株。此外，体内模型中基因表达的表征将有助于更好地了解脑膜炎球菌发病机制。