An Animal Model of Hemophagocytic Lymphohistiocytosis

噬血细胞淋巴组织细胞增多症的动物模型

基本信息

批准号：
7896615
负责人：
Michael Jordan
金额：
$ 37.5万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-10 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7896615
关键词：
Activated Lymphocyte Animal Model Antigen Presentation Antigens Birds Blood Bone Marrow Bone Marrow Cells Bone Marrow Transplantation Brain CD8B1 gene Caspase Cell physiology Cells Childhood Defect Dendritic Cells Disease Disease model Epstein-Barr Virus Infections Fever Genes Genetic Hemophagocytic Lymphohistiocytoses Immune Immune response Infection Interferon Type II Lead Liver Lymphocytic choriomeningitis virus Marrow Modeling Mus Mutation Natural Killer Cells Pancytopenia Pathogenesis Patients Phenotype Population Population Dynamics Process Production Regulatory T-Lymphocyte Relative (related person)Role Series Splenomegaly Stimulus Syndrome T-Lymphocyte Testing Viral Viral Antigens Virus Virus Diseases base bone cell type cytotoxic immune activation immunoregulation improved in vivo insight killings macrophage mortality novel perforin research study response

项目摘要

DESCRIPTION (provided by applicant): Hemophagocytic lymphohistiocytosis (HLH) is a childhood disorder of excessive and abnormal immune activation, characterized by severe damage to the bone marrow, and a mortality rate approaching 50%. Nearly all patients with HLH have a severe deficiency of cytotoxic killing by T and NK cells, and many of these patients have been found to harbor mutations in the gene encoding perforin. We developed a novel murine model of this disorder, in which perforin deficient (prf) mice are challenged with lymphocytic choriomeningitis virus (LCMV). Following infection, prf mice develop a phenotype that is nearly identical to HLH. Using this model, we have discovered that the HLH phenotype is directly driven by the abnormal overproduction of interferon gamma (IFN-g) by CD8+ T cells. Additionally, we have found that DC's from prf mice harbor increased amounts of viral antigen and acquire increased capacity to stimulate virus-specific T cells after infection. These findings implicate increased antigen presentation by DC populations as the underlying cause of IFN-g overproduction in prf mice, and suggest that perforin normally functions to down modulate antigen presentation. Multiple cell types that express perforin are known to interact with DC's. In order to identify which of these populations would normally down modulate stimulation by DC's, we have performed a series of cell depletion, transfer, and bone marrow transplantation experiments. These studies have revealed that perforin-expressing cell types can influence both DC function and in vivo IFN-g production, and suggest that CD8+ T cells are the most critical cell type exerting this regulatory effect. Based on our preliminary studies, we hypothesize that perforin-dependant cytotoxic killing of selected dendritic cells by CD8+ T cells limits the entry and/or persistence of antigen in DC populations, and thereby limits immune activation. To test our hypothesis, we will pursue the following specific aims: Aim 1.) Define how antigen handling and presentation differ between WT and prf DC subsets after LCMV infection. Aim 2.) Determine whether CD8+ T cells are the principle cell type that suppresses DC stimulatory function via a perforin-dependant mechanism. This project will lead to better understanding of how cytotoxic function regulates the immune response and lead to improved therapies for patients with HLH and perhaps many other immunopathologic disorders.

描述（申请人提供）：噬血细胞性淋巴组织细胞增多症（HLH）是一种儿童期免疫激活过度异常的疾病，其特点是严重损害骨髓，死亡率接近50%。几乎所有 HLH 患者都严重缺乏 T 细胞和 NK 细胞的细胞毒性杀伤能力，并且发现其中许多患者的穿孔素编码基因存在突变。我们开发了一种针对这种疾病的新型小鼠模型，其中穿孔素缺陷（prf）小鼠受到淋巴细胞性脉络膜脑膜炎病毒（LCMV）的攻击。感染后，prf 小鼠表现出与 HLH 几乎相同的表型。使用该模型，我们发现 HLH 表型是由 CD8+ T 细胞异常过量产生干扰素 γ (IFN-g) 直接驱动的。此外，我们发现来自 prf 小鼠的 DC 含有更多的病毒抗原，并且在感染后刺激病毒特异性 T 细胞的能力增强。这些发现表明 DC 群体的抗原呈递增加是 prf 小鼠中 IFN-g 过量产生的根本原因，并表明穿孔素通常起到下调抗原呈递的作用。已知多种表达穿孔素的细胞类型与 DC 相互作用。为了确定这些群体中哪些群体通常会下调 DC 的刺激，我们进行了一系列细胞去除、转移和骨髓移植实验。这些研究表明，表达穿孔素的细胞类型可以影响 DC 功能和体内 IFN-g 的产生，并表明 CD8+ T 细胞是发挥这种调节作用的最关键的细胞类型。基于我们的初步研究，我们假设 CD8+ T 细胞对选定树突状细胞的穿孔素依赖性细胞毒性杀伤限制了抗原在 DC 群体中的进入和/或持续存在，从而限制了免疫激活。为了检验我们的假设，我们将追求以下具体目标：目标 1.) 定义 LCMV 感染后 WT 和 prf DC 亚群之间的抗原处理和呈递有何不同。目标 2.) 确定 CD8+ T 细胞是否是通过穿孔素依赖性机制抑制 DC 刺激功能的主要细胞类型。该项目将有助于更好地了解细胞毒性功能如何调节免疫反应，并改善 HLH 以及许多其他免疫病理性疾病患者的治疗方法。