Role of pathogen-derived capping carbohydrates in altering immunity

病原体来源的封端碳水化合物在改变免疫力中的作用

• 批准号: 7468584
• 负责人: Christine A Petersen
• 金额: $ 17.73万
• 依托单位: IOWA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7468584
• 关键词: Acute; Adherence; Antigens; Area; Bacteria; Biological; Biological Models; Calmette-Guerin Bacillus; Carbohydrate Chemistry; Carbohydrates; Cells; Chemistry; Chronic; Chronic Disease; Cleaved cell; Collaborations; Complex; Dissection; Distal; Excision; Fibronectins; Fluorescence Microscopy; Genus Mycobacterium; Immune; Immune response; Immune system; Immunity; Immunologic Adjuvants; Immunologics; In Vitro; Infection; Inflammatory; Inflammatory Response; Injection of therapeutic agent; Knowledge; Latex Bead; Lead; Lectin; Leishmania; Ligands; Lipids; Localized; Mannose; Molecular Conformation; Monitor; Mycobacterium tuberculosis; Nature; Outcome; Parasites; Pathway interactions; Peptides; Phagocytosis; Phagolysosome; Phagosomes; Polysaccharides; Population Heterogeneity; Process; Production; Proteins; Public Health; Role; Signal Transduction; Structure; Surface; T-Lymphocyte Epitopes; Technology; Testing; Thinking; Vaccination; Vaccines; Viral; Virulence; Virulent; base; carbohydrate structure; cytokine; design; drug discovery; experience; gutted vector; in vivo; killings; lipoarabinomannan; lipophosphonoglycan; macrophage; mutant; mycobacterial; next generation; pathogen; peer; prevent; receptor; research study; response; size; sugar; surface coating; synthetic peptide

DESCRIPTION (provided by applicant): Structurally diverse carbohydrates are abundantly expressed on outer surfaces of pathogens. This project utilizes cap sugars of two surface carbohydrates, Lipophosphoglycans (LPG) and lipoarabinomannans (LAM), from Leishmania and Mycobacterium respectively. These two carbohydrate chains from virulent species delay phagosome maturation and promote a localized or systemic tolerogenic immune response that supports continuation of chronic infection. Unique cap sugars are associated with virulent Mycobacterial spp.; it is not known which specific portions of LPG/LAM cause immune alterations. Difficult carbohydrate chemistry precluded the ability to specifically test the role of this most-external portion of LAM/LPG. In this proposal, through breakthrough technology provided by chemist Dr. Nicola Pohl, this problem was overcome. Beads coated with LAM and LPG cap sugars have been produced. This proposal challenges two central hypotheses A) cap sugars are an immune- inhibitory portion of LAM and LPG and B) the in vitro and in vivo responses to four structurally different pathogen-derived cap sugars will differ in alteration of pathogen processing and destruction. Experiments outlined in this proposal are designed to 1) Confirm that synthetically-produced caps sugars have correct conformation and biologic activity 2) Determine how LAM or LPG mannose cap sugar-coated beads process in macrophages as compared to control phagocytosed beads, 3) Test the compared ability of bead-treated macrophages to kill internalized pathogens, 4) Characterize the in vivo immune response to LAM or LPG cap sugar-coated beads. We predict that beads coated with cap sugars derived from virulent Mycobacterium or Leishmania sp. will deter phagolysosome maturation and macrophage pathogen removal. In addition we predict that these cap sugars will inhibit in vivo bead clearance and promotion of a Th1 cytokine response. As pathogen-surface-expressed cap sugars partially determine pathogenic strains of bacteria and parasites, these studies will identify how changes in carbohydrate molecule cap structure lead to outcome-altering differences in immunity. PUBLIC HEALTH RELEVENCE: Understanding the specific role of cap sugars, the external surface coat for many pathogens, in altering host immune responses can lead to immediate and important discoveries in pathogen assemby that should be targeted for drug discovery. These pathogen surface- expressed cap sugars have been shown to predict differences between pathogenic and non- pathogenic strains of bacteria and parasites, therefore the proposed studies will provide a model system to identify the role of these molecules in determining virulence and how changes in cap structure leads to outcome-altering differences in immune responses. Due to the important function of carbohydrates in directing anti-pathogen immune responses, it is necessary to determine the specific role of pathogen-derived cap sugars in altering the in vivo and in vitro immune response.

描述（由申请人提供）：结构多样的碳水化合物在病原体的外表面大量表达。该项目利用两种表面碳水化合物的帽糖，即分别来自利什曼原虫和分枝杆菌的脂磷酸聚糖（LPG）和脂阿拉伯甘露聚糖（LAM）。来自有毒物种的这两条碳水化合物链延迟了吞噬体的成熟，并促进局部或全身的耐受性免疫反应，从而支持慢性感染的持续。独特的帽糖与有毒的分枝杆菌属有关；目前尚不清楚 LPG/LAM 的哪些特定部分会导致免疫改变。困难的碳水化合物化学使得无法专门测试 LAM/LPG 最外部部分的作用。在这项提案中，通过化学家 Nicola Pohl 博士提供的突破性技术，这个问题得到了克服。已生产出涂有 LAM 和 LPG 帽糖的珠子。该提案挑战了两个中心假设：A）帽糖是 LAM 和 LPG 的免疫抑制部分，B）对四种结构不同的病原体来源的帽糖的体外和体内反应将在病原体加工和破坏的改变方面有所不同。本提案中概述的实验旨在 1) 确认合成生产的帽糖具有正确的构象和生物活性 2) 确定与对照吞噬珠相比，LAM 或 LPG 甘露糖帽糖衣珠在巨噬细胞中的加工过程，3) 测试比较珠处理的巨噬细胞杀死内化病原体的能力，4) 表征对 LAM 或 LPG 帽糖衣珠的体内免疫反应。我们预测，涂有来自有毒分枝杆菌或利什曼原虫的帽糖的珠子。将阻止吞噬溶酶体成熟和巨噬细胞病原体清除。此外，我们预测这些帽糖将抑制体内珠子清除并促进 Th1 细胞因子反应。由于病原体表面表达的帽糖部分决定了细菌和寄生虫的致病菌株，这些研究将确定碳水化合物分子帽结构的变化如何导致改变免疫结果的差异。公共卫生相关性：了解帽糖（许多病原体的外表面涂层）在改变宿主免疫反应中的具体作用，可以在病原体组装方面产生直接而重要的发现，这些发现应该成为药物发现的目标。这些病原体表面表达的帽糖已被证明可以预测细菌和寄生虫的致病性和非致病性菌株之间的差异，因此拟议的研究将提供一个模型系统来识别这些分子在确定毒力中的作用以及帽结构如何变化导致免疫反应中改变结果的差异。由于碳水化合物在指导抗病原体免疫反应中发挥重要作用，因此有必要确定病原体来源的帽糖在改变体内和体外免疫反应中的具体作用。