Listeriosis Pathogenesis: Effect of Serogroup-specific Wall Teichoic Acid Changes

李斯特菌病发病机制：血清群特异性壁磷壁酸变化的影响

• 批准号: 8582407
• 负责人: PAUL Edwin ORNDORFF
• 金额: $ 17.8万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8582407
• 关键词: Anabolism; Animals; Area; Attenuated; Biochemical; Biological; Biological Assay; Cells; Deletion Mutation; Development; Diagnosis; Diagnostic; Diagnostic Specificity; Disease; Disease Outbreaks; Enterocytes; Epidemiologic Studies; Generations; Genes; Growth; Health; Human; Immune; Immunocompromised Host; In Vitro; Individual; Infection; Inflammatory; Intestines; Knowledge; Laboratories; Lectin; Listeria monocytogenes; Listeriosis; Modality; Modeling; Mononuclear; Mus; National Health Policy; Oral; Pathogenesis; Pathogenicity; Phagocytes; Pregnant Women; Prevalence; Procedures; Production; Property; Risk Assessment; Structure; TNF gene; Teichoic Acids; Therapeutic; Virulence; Virulent; Work; base; cell growth; cytokine; foodborne pathogen; improved; in vivo; indexing; killings; macrophage; monolayer; mutant; neonate; public health relevance; research study; sugar

DESCRIPTION (provided by applicant): Great strides have been made in understanding Listeria monocytogenes pathogenesis, especially at the cell biological level. One reason for this progress has been the extensive use of a single serogroup 1/2 L. monocytogenes strain, EGD. However, representative strains from other more prevalent serogroups, including serogroup 4, have remained understudied. Serogroup 4 strains constitute the preponderance of disease associated isolates from humans and other animals. Listerial serogroups are defined by their wall teichoic acid (WTA) structure. All listerial isolates have one of two fundamentally different WTA structures--those represented by the 1/2 serogroup structure and those represented by serogroup 4 structure. Recent independent studies indicate that certain alterations to serogroup 4 WTA composition are profoundly attenuating. In this proposal we examine the pathogenesis of a mouse oral virulent serogroup 4 strain. We have one specific aim: 1) Construct and characterize mutants that have altered serogroup 4 wall teichoic acid (WTA) composition. We will systematically alter the serogroup 4 WTA composition and correlate compositional changes to alterations in pathogenicity in vivo and in vitro. This aim has three objectives: (a) Mutant construction and biochemical characterization; allelic exchange will be employed to introduce in-frame deletion mutations into genes whose products are required for the generation of, and the proper substitution of the serogroup 4 WTA repeat unit. (b) Mutant characterization in vitro; intracellular growth and cell-to-cell spread will be assessed in cultured mouse enterocyte and macrophage monolayers. (c) Mutant characterization in vivo and ex vivo; the oral virulence of each mutant will be determined in infective index experiments that assess the degree of translocation of the mutants from the intestinal lumen. Additionally, the elicitation of inflammatory cell infiltrates, phagocytic killing by PMN and mononuclear phagocytes, and level of TNF production will be examined for each WTA mutant. Overall, we anticipate that our results will extend our knowledge of listerial pathogenesis in a highly relevant serogroup. Additionally, our results have the potential to impact national health policies and procedures in several areas. For example: (i) Risk assessment-a knowledge of how serogroup 4 WTA composition influences virulence could facilitate the development of simple lectin based assays to assess the need for product recalls in cases of listerial contamination. (ii) Diagnostics-a knowledge how WTA composition influences pathogenic potential and disease presentation could facilitate diagnosis, improve the specificity of diagnostic assays, and improve the power of epidemiological studies. (iii) Therapies--specific therapeutic strategies could expand treatment modalities (e.g., ones tailored to disrupt specific steps in WTA biosynthesis).

描述（由申请人提供）：在理解单核细胞增生李斯特菌发病机制方面取得了很大进展，特别是在细胞生物学水平。这一进展的一个原因是广泛使用单一血清群1/2 L。单核细胞增生菌株EGD。然而，来自其他更流行的血清群（包括血清群4）的代表性菌株仍未得到充分研究。血清群4菌株构成了来自人类和其他动物的疾病相关分离株的优势。李斯特菌血清群由其壁磷壁酸（WTA）结构定义。所有分离株都具有两种根本不同的WTA结构之一-由1/2血清群结构代表的WTA结构和由血清群4结构代表的WTA结构。最近的独立研究表明，血清组4 WTA组成的某些改变是深刻的衰减。在这个提议中，我们研究了小鼠口服毒力血清组4菌株的发病机制。我们有一个具体的目标：1）构建和表征突变体，改变血清组4壁磷壁酸（WTA）的组成。我们将系统地改变血清组4 WTA组成，并将组成变化与体内和体外致病性变化相关联。这一目标有三个目标：（a）突变体构建和生物化学表征;等位基因交换将用于将框内缺失突变引入基因中，所述基因的产物是血清群4 WTA重复单元的产生和适当取代所需的。(b)体外突变体表征;将在培养的小鼠肠上皮细胞和巨噬细胞单层中评估细胞内生长和细胞间扩散。(c)体内和离体突变体表征;将在评估突变体从肠腔移位程度的感染指数实验中确定每种突变体的经口毒力。此外，将检查每种WTA突变体的炎症细胞浸润、PMN和单核吞噬细胞的吞噬杀伤以及TNF产生水平。总体而言，我们预计，我们的研究结果将扩大我们的知识，在一个高度相关的血清群的发病机制。此外，我们的研究结果有可能在几个领域影响国家卫生政策和程序。举例来说：（i）风险评估-了解血清组4 WTA成分如何影响毒力，有助于开发简单的基于凝集素的检测方法，以评估是否需要在细菌污染的情况下回收产品。(ii)诊断知识WTA组成如何影响致病潜力和疾病的介绍，可以促进诊断，提高诊断检测的特异性，并提高流行病学研究的力量。(iii)治疗----具体的治疗策略可以扩大治疗方式（例如，定制以破坏WTA生物合成中的特定步骤）。