Otitis media-associated pneumococcal genes

中耳炎相关肺炎球菌基因

• 批准号: 7247972
• 负责人: JING-REN ZHANG
• 金额: $ 33.71万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7247972
• 关键词: Acute; Adherence; Adhesives; Animals; Antibiotic Resistance; Antibodies; Bacterial Adhesins; Binding; Cells; Cellular Immunity; Child; Chinchilla (genus); Disease; Epithelial Cells; Epithelium; Foundations; Genes; Hand; Human; Immunity; Infection; Inflammation; Inflammatory Response; Laboratories; Lead; Libraries; Liquid substance; Mediating; Membrane Proteins; Modeling; Molecular; Mucous body substance; Mutation; Numbers; Open Reading Frames; Otitis Media; Pathogenesis; Patients; Pneumococcal Colonization; Pneumococcal Infections; Pneumococcal vaccine; Pneumonia; Polysaccharides; Prevention; Principal Investigator; Production; Protein S; Proteins; Public Health; Rattus; Screening procedure; Serotyping; Serum; Streptococcus pneumoniae; Streptococcus pyogenes; Surface; Testing; Vaccination; Vaccines; Virulent; base; capsule; improved; in vivo; middle ear; multiple myeloma M Protein; mutant; novel therapeutics; pathogen; prevent; programs; therapeutic target

DESCRIPTION (provided by applicant): Streptococcus pneumoniae (the pneumococcus) is the most common cause of acute otitis media (OM) in children. The pathogenesis of pneumococcal infection in the middle ear depends on bacterial adherence to mucosal epithelial cells. Attachment to mucosal surfaces not only facilitates pneumococcal colonization in the middle ear, but also triggers inflammatory responses and induces mucus secretion. Profound inflammation and excessive secretion are the hallmarks of pneumococcal OM. In contrast, the mechanisms underlying pneumococcal adherence to the mucosal surface of the middle ear are poorly understood. Our long-term objectives are to elucidate the molecular mechanisms of pneumococcal adherence, and to evaluate the potential of interfering with pneumococcal adherence as a strategy to prevent OM and other pneumococcal infections. We have already isolated 14 mutants of S. pneumoniae that are substantially reduced in their ability to bind to human middle ear epithelial cells. One of these mutants carries an insertional mutation in an open reading frame (designated MplA) that is homologous to the M protein of Streptococcus pyogenes. We thus hypothesize that surface proteins of S. pneumoniae promote pneumococcal adherence to middle ear epithelium. This proposal will test this hypothesis by systematically identifying and characterizing pneumococcal proteins that are associated with adherence of S. pneumoniae to human middle ear epithelial cells. Our Specific Aims are to: 1) Characterize the mechanism of MplAmediated adherence. We will determine (i) whether the MplA protein is expressed at the surface of S. pneumoniae, (ii) which domain of MplA mediates binding to host cells, and (iii) whether the mlpA gene and its protein product are conserved in pneumococcal strains isolated from OM patients. 2) Identify the genes encoding new S. pneumoniae adhesins. We will accomplish this aim by (i) characterizing the 13-uncharactedzed adherence-deficient mutants and (ii) screening a library of signature-tagged pneumococcal mutants that were recently established in our laboratory. 3) Determine the ability of adhesins to induce protective immunity against S. pneumoniae infection in the middle ear. MplA and other adhesin proteins identified in Aim #2 will be used to immunize the OM rat model. Protective activity will be assessed by (i) bacterial burden and (ii) inflammation in the middle ear following challenge with virulent pneumococci. The resulting information will not only enhance our understanding of OM pathogenesis, but may also lead to improved prevention of OM cause by S. pneumoniae.

描述（由申请人提供）：肺炎链球菌（肺炎球菌）是儿童急性中耳炎（OM）的最常见原因。中耳肺炎球菌感染的发病机制取决于细菌粘附于粘膜上皮细胞。附着在粘膜表面不仅有利于肺炎球菌在中耳定植，还会引发炎症反应并诱导粘液分泌。严重炎症和过度分泌是肺炎球菌 OM 的标志。相比之下，人们对肺炎球菌粘附到中耳粘膜表面的机制知之甚少。我们的长期目标是阐明肺炎球菌粘附的分子机制，并评估干扰肺炎球菌粘附作为预防 OM 和其他肺炎球菌感染的策略的潜力。我们已经分离出 14 种肺炎链球菌突变体，它们与人中耳上皮细胞结合的能力大大降低。其中一种突变体在开放阅读框（称为 MplA）中携带插入突变，该插入突变与化脓性链球菌的 M 蛋白同源。因此，我们假设肺炎链球菌的表面蛋白促进肺炎球菌粘附到中耳上皮。该提案将通过系统地识别和表征与肺炎链球菌粘附到人中耳上皮细胞相关的肺炎球菌蛋白来检验这一假设。我们的具体目标是： 1) 描述 MplA 介导的依从机制。我们将确定 (i) MplA 蛋白是否在肺炎链球菌表面表达，(ii) MplA 的哪个结构域介导与宿主细胞的结合，以及 (iii) mlpA 基因及其蛋白产物在肺炎球菌菌株中是否保守从 OM 患者中分离出来。 2) 鉴定编码新肺炎链球菌粘附素的基因。我们将通过 (i) 表征 13 个未表征的粘附缺陷突变体和 (ii) 筛选我们实验室最近建立的带有特征标记的肺炎球菌突变体库来实现这一目标。 3) 确定粘附素诱导中耳抵抗肺炎链球菌感染的保护性免疫的能力。 MplA 和目标 #2 中鉴定的其他粘附素蛋白将用于免疫 OM 大鼠模型。保护活性将通过（i）细菌负荷和（ii）有毒力肺炎球菌攻击后中耳的炎症来评估。由此产生的信息不仅将增强我们对 OM 发病机制的了解，还可能改善对肺炎链球菌引起的 OM 的预防。