Role of sialylated LPS in H. influenzae otitis media

唾液酸化脂多糖在流感嗜血杆菌中耳炎中的作用

• 批准号: 6494256
• 负责人: RICHARD GOLDSTEIN
• 金额: $ 8.05万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-25 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6494256
• 关键词: Haemophilus influenzae; bacteria infection mechanism; bacterial genetics; chinchilla; disease /disorder model; lipopolysaccharides; magnetic resonance imaging; mass spectrometry; mutant; otitis media; pathologic process; protein structure function; sialate; virulence

DESCRIPTION (provided by applicant): Nontypable Haemophilus influenzae (NTHi) is a major cause of acute otitis media (AOM) accounting for 20-30% of all episodes. There is also evidence that NTHi is the most frequent pathogen in children with recurrent episodes of AOM. The extensive heterogeneity of outer membrane proteins has been an impediment to identifying effective vaccine candidates against NTHi. In animal models, membrane protein antigens tend to induce homologous, but not heterologous protection. To date, the PI's research on H. influenzae has exclusively focused on phylogenetic characterization of species natural population structure and its use to survey degree of conservation of potential outer membrane protein targets. Because few essential virulence factors have been identified in the pathogenesis of AOM caused by NTHi, the PI carried out a preliminary pilot study to test the hypothesis that sialic acid, a terminal sugar of NTHi lipopolysaccharicle, might be an essential virulence factor in AOM, analogous to the virulence role of sialic acid of LPS in gonococcal and meningococcal infections. These studies capitalized upon the availability of: (i) isogenic pairs of wild-type and LPS sialylation deficient mutants; (ii) the chinchilla animal model for experimental otitis media and (iii) the fine structural analysis of LPS, including data on organisms obtained ex-vivo from the animal model. This pilot study revealed attenuation of infection by the sialic acid deficient mutant strains compared to infection with wild-type organisms. This is consistent with prior studies showing that sialic acid deficient mutants of NTHi are relatively susceptible to complement mediated bactericidal killing by pooled human sera. The current R21 proposal aims to expand this preliminary evaluation of the role of sialic acid in the pathogenesis of AOM. It amalgamates population biology, a validated animal model of AOM, microbial genetics, and structural analysis to determine the role of sialic acid as virulence factor. These data will pave the way for further studies that could be supported by a future R01 application.

描述（由申请人提供）：不富裕的流感嗜血杆菌（NTHI）为 急性中耳炎（AOM）的主要原因占所有发作的20-30％。 也有证据表明，NTHI是儿童中最常见的病原体 AOM的经常发作。外膜的广泛异质性 蛋白质一直是识别有效疫苗候选物的障碍 反对Nthi。在动物模型中，膜蛋白抗原倾向于诱导 同源，但不是异源保护。 迄今为止，PI对流感疫苗的研究仅关注 物种自然种群结构及其的系统发育表征 用于调查潜在外部保护程度 膜蛋白靶标。因为很少的基本毒力 在NTHI引起的AOM的发病机理中已经鉴定了因子 进行了一项初步的试点研究，以检验唾液酸，A nthi脂多腺char菜的末期糖可能是必不可少的毒力 AOM中的因子，类似于LPS唾液酸的毒力作用 淋球菌和脑膜炎球菌感染。这些研究大写了 可用性：（i）野生型和lps溶性的等源性对 突变体； （ii）实验中耳炎的龙猫动物模型和 （iii）LP的精细结构分析，包括有关获得的生物的数据 动物模型的前体。这项试点研究揭示了 与感染相比，唾液酸缺乏突变菌株感染 野生型生物。这与先前的研究一致，表明唾液 NTHI的酸缺乏突变体相对容易介导 通过合并的人血清杀菌杀菌。 当前的R21提案旨在扩大对角色的初步评估 唾液酸在AOM的发病机理中的。它使种群生物学合并， 经过验证的AOM动物模型，微生物遗传学和结构分析 确定唾液酸作为毒力因子的作用。这些数据将铺平 进一步研究的方法可以由未来的R01应用程序支持。