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(申请人提供)：单核细胞增生性李斯特菌(Lm)是一个重要的病原体研究，因为：1)它引起威胁生命的食源性感染和重大的公共卫生问题，2)它是一种遗传易驯化的生物，具有独特的细胞内生活方式，用作了解哺乳动物细胞生物学的工具，以及3)系统性(IV.)李斯特菌病是一种高度重复性的感染，免疫学家经常用它来研究细胞介导的免疫反应。由于缺乏接近模拟人类疾病的小动物模型，我们仍然对LM的口服传播知之甚少，也不知道为什么发生严重胃肠炎、败血症和脑膜脑炎的先天易感性因个体而异。为了解决这一知识差距，我们最近开发了一种新的口腔李斯特菌病模型，使用喂食受LM污染的食物的小鼠。这种自然喂养模型显示，在易感(BALB)和耐药(B6)小鼠中，LM在肠道定植和系统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中存活的肠道适应的LM如何能够定植在肠道粘膜上，并作为一个病灶持续种植在无法快速清除肠道感染的易感小鼠的周围组织中。由于绝大多数李斯特菌病住院患者在某种程度上可以被认为是免疫低下，长期以来人们一直认为保护性免疫反应对于将感染限制在耐药个体中的轻度胃肠炎至关重要。我们的中心假设预测，一种这样的先天免疫机制是记忆表型CD8+T细胞亚群快速分泌干扰素。我们推测T细胞来源的干扰素可以在B6小鼠中快速启动清除机制，而BALB小鼠中CD8+T细胞激活的延迟允许LM指数级复制并扩散到全身组织。这项应用有三个具体目标：(1)确定结肠中支持LM生长的细胞类型，从而成为保护性先天免疫反应的靶点；(2)确定在摄入LM后快速分泌干扰素的CD8+T细胞的特定亚群，并证明这种T细胞来源的干扰素可以迅速限制结肠中LM的细胞内生长；(3)鉴定依赖于干扰素的先天免疫机制，这些机制促进LM从肠道传播后在周围组织中快速清除。这一应用中的一个关键策略将是使用一种独特的领养转移系统，在该系统中，来自有反应的小鼠的T细胞被注入MHC匹配的无反应的小鼠。这一强大的方法将使我们能够特异性地分离CD8+T细胞快速产生的干扰素的功能，同时保持所有其他先天免疫机制不变。拟议研究的预期结果是：[1]对食源性LM的致病生活方式有了重大的新见解，[2]更好地理解了决定宿主对细胞内细菌病原体的抵抗力/敏感性的先天免疫机制。 与公共卫生相关：单核细胞增多性李斯特菌(Lm)通过摄入受污染的“即食”食品传播，如未经巴氏灭菌的奶酪、熟食肉类和农产品。人类感染的严重程度差异很大，从轻微的自限性胃肠炎到危及生命的败血症和脑膜脑炎，导致这一范围疾病的宿主易感因素尚未确定。在这项研究中，我们测试了抵抗的想法 个人对感染的反应是迅速产生一种保护蛋白，激活多种杀死机制，迅速清除细菌，而易感人群则缺乏协调这种快速免疫反应的能力。