HAEMOPHILUS INFLUENZAE B VIRULENCE--ROLE OF HAEMOCIN

B 型流感嗜血杆菌毒力——血红素的作用

• 批准号: 2064656
• 负责人: JOHN J LIPUMA
• 金额: $ 10.69万
• 依托单位: ALLEGHENY UNIVERSITY OF HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2064656
• 关键词: Haemophilus influenzae; antibacterial antibody; bacterial cytopathogenic effect; bacterial genetics; bacterial meningitis; bacterial proteins; bacteriocin; child (0-11); disease /disorder model; electron microscopy; enzyme linked immunosorbent assay; gene mutation; genetic library; genetic strain; histopathology; human tissue; infant animal; laboratory rat; molecular cloning; nucleic acid sequence; protein purification; protein structure function; recombinant DNA; respiratory epithelium; transposon /insertion element; vascular endothelium; virulence; western blottings

DESCRIPTION (Adapted from applicant's abstract): H. influenzae is a human-specific bacterial pathogen responsible for a variety of serious infections in children, including pneumonia, cellulitis, septic arthritis, and epiglottitis. Further, H. influenzae is the most common cause of bacterial meningitis in the United States, affecting approximately 12,000 children annually. Despite recent advances in antimicrobial therapy, the morbidity and mortality resulting from H. influenzae infection has changed little during the past decade. Two factors clearly distinguish strains of H. influenzae which cause invasive infection from relatively avirulent members of this species: the presence of polysaccharide capsule composed of polyribosyl ribitol phosphate (PRP) and the production of a bacteriocin protein termed haemocin. Whereas the PRP capsule has been extensively examined as a virulence factor, the role of haemocin has not been investigated. This proposal seeks to investigate the role of haemocin in the virulence of H. influenzae. To unambiguously define this role, the genetic basis of haemocin production will be determined, and the gene(s) encoding haemocin will be cloned. Mutagenesis of the cloned haemocin gene will be performed to construct isogeneic strains of H. influenzae differing only in their ability to produce haemocin. These isogeneic strains will then be used to determine the effect of haemocin production in virulence by using a relevant animal model of H. influenzae infection. The relative abilities of HMC+ and HMC-strains to colonize and to invade infant rats will be assessed. Another goal of this project is to purify and characterize the haemocin protein. The potential role of haemocin in contributing to virulence by mediating a direct toxic effect upon mammalian host cells will be examined by investigating the effects of haemocin production upon relevant human tissue in vitro. Should haemocin prove important in virulence, the availability of the cloned haemocin gene and its protein product will permit further investigations designed to define new strategies for the prevention of H. influenzae infection.

描述（改编自申请人的摘要）：流感嗜血杆菌是一种 人类特有的细菌病原体导致多种严重的 儿童感染，包括肺炎、蜂窝组织炎、化脓性关节炎， 和会厌炎。 此外，流感嗜血杆菌是最常见的原因 美国细菌性脑膜炎，影响约 12,000 人 儿童每年。 尽管抗菌治疗最近取得了进展， 流感嗜血杆菌感染导致的发病率和死亡率发生了变化 过去十年很少。 有两个因素可以清楚地区分菌株 流感嗜血杆菌，由相对无毒的病毒引起侵袭性感染 该物种的成员：存在由多糖胶囊组成的 聚核糖核糖醇磷酸 (PRP) 的制备和细菌素的生产 称为血红素的蛋白质。 而 PRP 胶囊已被广泛应用 作为一种毒力因子，血红素的作用尚未得到证实。 调查了。 该提案旨在研究血红素在毒力中的作用 流感嗜血杆菌。 为了明确定义这一作用，遗传基础 将确定血红素的产量，并且编码血红素的基因 将被克隆。 将进行克隆的血红素基因的诱变 构建流感嗜血杆菌的同基因菌株，其差异仅在于 产生血红素的能力。 这些同基因菌株将被用于 通过使用确定血红素产生对毒力的影响 流感嗜血杆菌感染的相关动物模型。 相对能力 HMC+ 和 HMC- 菌株定殖并侵入幼鼠的情况将 评估。 该项目的另一个目标是纯化和表征 血红素蛋白。 血红素在促进中的潜在作用 通过介导对哺乳动物宿主细胞的直接毒性作用来产生毒力 通过调查血红素产生对 体外相关人体组织。 血红素是否应该被证明很重要 毒力、克隆血红素基因及其蛋白质的可用性 产品将允许进一​​步调查旨在定义新的 预防流感嗜血杆菌感染的策略。