Role of Rapid IFNg Secretion by CD*+ T cells in Clearance of Food Borne Listeria

CD* T 细胞快速分泌 IFNg 在清除食源性李斯特菌中的作用

• 批准号: 8343492
• 负责人: SARAH E. F. D'ORAZIO
• 金额: $ 36.23万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-20 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8343492
• 关键词: Address; Adoptive Transfer; Animal Model; Antigens; Bacteria; CD8-Positive T-Lymphocytes; CD8B1 gene; Cells; Cellular biology; Cheese; Colon; Dendritic Cells; Disease; Dose; Eating; Enterocytes; Feces; Food; Gastroenteritis; Gastrointestinal tract structure; Genes; Growth; Hepatocyte; Host resistance; Human; Immune; Immune response; Immunologist; In Vitro; Individual; Infection; Inflammatory; Ingestion; Interferons; Interleukin-12; Interleukin-18; Intestinal Mucosa; Intestines; Intravenous; Kinetics; Knowledge; Lamina Propria; Left; Life; Life Style; Listeria; Listeria monocytogenes; Listeriosis; Liver; Lymphocyte; M cell; Mammalian Cell; Meat; Memory; Meningoencephalitis; Modeling; Mus; Natural Immunity; Oral; Organism; Outcome; Pathway interactions; Patients; Peripheral; Phenotype; Population; Predisposition; Process; Proteins; Public Health; Research Personnel; Resistance; Role; Seeds; Sepsis; Septicemia; Severities; Signal Transduction; Small Intestines; Source; Spleen; Stomach; Symptoms; System; T-Lymphocyte; T-Lymphocyte Subsets; Testing; Time; Tissues; adaptive immunity; cell mediated immune response; cell type; cytokine; feeding; foodborne; foodborne infection; human disease; in vivo; insight; killings; macrophage; mortality; oral infection; pathogen; receptor; response; tool; transmission process

DESCRIPTION (provided by applicant): Listeria monocytogenes (Lm) is important an important pathogen to study because: 1) it causes life threatening food borne infections of significant public health concern, 2) it is a genetically tractable organism with a unique intracellular lifestyle used as a tool for understanding the cell biology of mammalian cells, and 3 systemic (i.v.) listeriosis is a highly reproducible infection frequently used by immunologists to study cell- mediated immune responses. Due to the lack of a small animal model that closely mimics human disease, we still know very little about oral transmission of Lm, or why the innate susceptibility to developing severe gastroenteritis, sepsis, and meningoencephalitis varies among individuals. To address this knowledge gap, we recently developed a new model of oral listeriosis using mice fed Lm-contaminated food. This natural feeding model revealed clear differences in the ability of Lm to colonize the gut and spread systemically in susceptible (BALB) vs. resistant (B6) mice. Thus, for the first time, we can now study how gut-adapted Lm that survive digestive processes in the stomach are able to colonize the intestinal mucosa and serve as a nidus for continual seeding of peripheral tissues in susceptible mice unable to quickly clear the gut infection. Since the vast majority of patients hospitalized with listeriosis can be considered immune compromised in some way, it has long been thought that protective immune responses were critical for limiting the infection to a mild gastroenteritis in resistant individuas. Our central hypothesis predicts that one such innate immune mechanism is the rapid secretion of IFN¿ by a subset of memory phenotype CD8+ T cells. We postulate that T cell-derived IFN¿ can rapidly initiate clearance mechanisms in B6 mice and that the delay in activation of CD8+ T cells in BALB mice allows Lm to replicate exponentially and spread to systemic tissues. This application has three specific aims: (1) to identify the cell types in the colon that support Lm growth and thus, serve as the targets of protective innate immune responses; (2) to identify the specific subsets of CD8+ T cells that rapidly secrete IFN¿ after ingestion of Lm and show that this T cell-derived IFN¿ can rapidly limit the intracellular growth of Lm in the colon; (3) to idenify IFN¿-dependent innate immune mechanisms that promote rapid clearance of Lm in peripheral tissues after dissemination from the gut. A key strategy in this application will be the use of a unique adoptive transfer system wherein T cells from a responsive mouse are injected into a MHC-matched non-responsive mouse. This powerful approach will allow us to specifically isolate the function of IFN¿ rapidly produced by CD8+ T cells while leaving all other innate immune mechanisms intact. The expected outcomes of the proposed studies are: [1] significant new insights into the pathogenic life style of food borne Lm, and [2] a better understanding of the innate immune mechanisms that determine host resistance/susceptibility to intracellular bacterial pathogens. PUBLIC HEALTH RELEVANCE: Listeria monocytogenes (Lm) is transmitted by ingestion of contaminated "ready-to-eat" food products such as unpasteurized cheeses, deli meats, and produce. Human infections vary greatly in severity from a mild, self- limiting gastroenteritis to life-threatening septicemia and meningoencephalitis, and the host susceptibility factors that contribute to this range of disease are not defined. In this study, we test the idea that resistant individuals respond to infection by rapidly producing a protective protein that activates multiple killing mechanisms that quickly clear the bacteria while susceptible individuals lack the ability t orchestrate this rapid immune response.

描述（由申请人提供）：单核细胞增生李斯特氏菌（Lm）是一种重要的研究病原体，因为：1）它会导致危及生命的食源性感染，引起重大公共卫生问题，2）它是一种遗传上易于控制的生物体，具有独特的细胞内生活方式作为了解哺乳动物细胞生物学的工具，3 系统性（静脉注射）李斯特菌病是一种高度可重复的感染，免疫学家经常使用它来研究细胞介导的免疫反应。由于缺乏密切模仿人类疾病的小动物模型，我们对 Lm 的口腔传播仍然知之甚少，也不知道为什么个体之间对严重胃肠炎、败血症和脑膜脑炎的先天易感性各不相同。我们最近开发了一种新的口腔李斯特菌病模型，使用喂食 Lm 污染食物的小鼠，这种自然喂养模型揭示了 Lm 在易感人群 (BALB) 和对照组中的肠道定植和系统性传播的能力存在明显差异。因此，我们现在第一次可以研究在胃消化过程中存活下来的肠道适应性 Lm 如何能够在易感小鼠的肠粘膜上定植并作为外周组织持续接种的病灶。由于绝大多数因李斯特菌病住院的患者在某种程度上都被认为是免疫受损的，因此长期以来人们一直认为保护性免疫反应对于将感染限制为轻度耐药性胃肠炎至关重要。我们的中心假设预测，一种这样的先天免疫机制是 IFN 的快速分泌。我们假设 T 细胞衍生的 IFN¿可以在 B6 小鼠中启动快速清除机制，并且 BALB 小鼠中 CD8+ T 细胞激活的延迟使 Lm 呈指数复制并扩散到全身组织。该应用具有三个具体目标：(1) 识别结肠中的细胞类型。支持 Lm 生长，因此可作为保护性先天免疫反应的目标 (2) 识别快速分泌 IFN 的特定 CD8+ T 细胞亚群；摄入 Lm 后，表明这种 T 细胞衍生的 IFN¿ (3)鉴定IFN¿可以快速限制Lm在结肠细胞内的生长；依赖于先天免疫机制，促进 Lm 从肠道传播后在外周组织中快速清除。该应用的一个关键策略是使用独特的过继转移系统，将来自反应性小鼠的 T 细胞注射到 MHC 匹配的体内。这种强大的方法将使我们能够特异性分离 IFN 的功能。所提出的研究的预期结果是：[1]对食源性 Lm 致病生活方式的重要新见解，以及[2]对先天性免疫机制的更好理解。决定宿主对细胞内细菌病原体的抵抗力/易感性的免疫机制。 公共卫生相关性：单核细胞增多性李斯特菌 (Lm) 通过摄入受污染的“即食”食品（例如未经高温消毒的奶酪、熟食肉类和农产品）传播，人类感染的严重程度有很大差异，从轻微的自限性胃肠炎到严重程度不等。危及生命的败血症和脑膜脑炎，以及导致这一系列疾病的宿主易感因素尚未确定。在本研究中，我们测试了这些疾病。认为阻力 个体通过快速产生一种保护性蛋白质来应对感染，这种保护性蛋白质激活多种杀灭机制，快速清除细菌，而易感个体缺乏协调这种快速免疫反应的能力。