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: 8493992
• 负责人: SARAH E. F. D'ORAZIO
• 金额: $ 34.33万
• 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/8493992
• 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.

描述（由申请人提供）：单核增生李斯特菌（Listeria monocytogenes, Lm）是一种重要的研究病原体，因为：1)它引起危及生命的食源性感染，具有重大的公共卫生问题；2)它是一种遗传易感的生物，具有独特的细胞内生活方式，被用作理解哺乳动物细胞生物学的工具；3系统性（内源性）李斯特菌病是一种高度可复制的感染，经常被免疫学家用来研究细胞介导的免疫反应。由于缺乏与人类疾病非常相似的小动物模型，我们对Lm的口腔传播知之甚少，也不知道为什么对严重胃肠炎、败血症和脑膜脑炎的先天易感性因人而异。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。这种自然喂养模型揭示了Lm在易感（BALB）和耐药（B6）小鼠中定植肠道和全身传播能力的明显差异。因此，我们现在第一次可以研究在胃消化过程中存活的肠道适应的Lm如何能够在肠粘膜上定植，并作为无法快速清除肠道感染的易感小鼠的外周组织持续播种的病灶。由于绝大多数因李斯特菌病住院的患者在某种程度上可被视为免疫功能受损，因此长期以来人们一直认为，保护性免疫反应对于将耐药个体的感染限制为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IFN¿。我们假设T细胞来源的IFN¿可以在B6小鼠中快速启动清除机制，并且在BALB小鼠中CD8+ T细胞激活的延迟允许Lm呈指数级复制并扩散到全身组织。该应用程序有三个具体目的：(1)确定结肠中支持Lm生长的细胞类型，从而作为保护性先天免疫反应的目标；(2)鉴定摄入Lm后快速分泌IFN¿的CD8+ T细胞的特异性亚群，并表明这种T细胞来源的IFN¿可以快速限制Lm在结肠内的细胞内生长；(3)确定IFN依赖的先天免疫机制，促进Lm从肠道传播后外周组织中的快速清除。该应用的关键策略是使用一种独特的过继性转移系统，其中将来自应答小鼠的T细胞注射到mhc匹配的非应答小鼠中。这种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IFN¿的功能，同时保持所有其他先天免疫机制完整。所提出的研究的预期结果是：[1]对食源性Lm的致病生活方式有重要的新见解，[2]更好地了解决定宿主对细胞内细菌病原体抗性/易感性的先天免疫机制。