An Animal Model of Hemophagocytic Lymphohistiocytosis

噬血细胞淋巴组织细胞增多症的动物模型

• 批准号: 7837337
• 负责人: Michael Jordan
• 金额: $ 24.9万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7837337
• 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; Relative (related person); Role; Series; Splenomegaly; Stimulus; Syndrome; T-Lymphocyte; Testing; Viral; Viral Antigens; Virus; Virus Diseases; base; bone; cell type; cytotoxic; immunoregulation; improved; in vivo; insight; killings; macrophage; mortality; novel; perforin; research study; response

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.

淋巴淋巴虫组织细胞增多症（HLH）是一种过度和异常免疫的儿童疾病 激活，其特征是严重损坏骨髓，死亡率接近50％。 几乎所有HLH患者都严重缺乏T和NK细胞的细胞毒性杀伤，许多 这些患者被发现在编码穿孔蛋白的基因中含有突变。我们开发了一本小说 这种疾病的鼠模型，在这种疾病中，淋巴细胞挑战性能缺乏（PRF）小鼠 绒毛膜炎病毒（LCMV）。感染后，PRF小鼠发展出一种与 HLH。使用此模型，我们发现HLH表型直接由异常驱动 CD8+ T细胞对干扰素伽马（IFN-G）的生产过多。此外，我们发现DC来自PRF 小鼠携带的病毒抗原量增加并获得增加刺激病毒特异性T的能力 感染后的细胞。这些发现暗示了DC种群增加的抗原表现为 PRF小鼠IFN-G过量生产的根本原因，并建议穿孔蛋白通常起作用 调节抗原表现。已知多种表达穿孔蛋白的细胞类型与DC相互作用。在 为了确定这些人群中的哪个通常会减少DC的调节刺激，我们有 进行了一系列细胞耗竭，转移和骨髓移植实验。这些研究 已经揭示了表达穿孔蛋白的细胞类型可以影响直流功能和体内IFN-G功能 生产，并表明CD8+ T细胞是发挥这种调节作用的最关键细胞类型。 基于我们的初步研究，我们假设所选的依赖性依赖性的细胞毒性杀死 CD8+ T细胞的树突状细胞限制了DC种群中抗原的进入和/或持续性，从而限制 限制免疫激活。要检验我们的假设，我们将追求以下特定目的：目标1.）定义 LCMV感染后，WT和PRF DC子集之间的抗原处理和表现如何不同。目标2.） 确定CD8+ T细胞是否是通过A抑制直流刺激功能的原理细胞类型 依赖穿孔素的机制。该项目将更好地了解细胞毒性功能 调节免疫反应并导致改善HLH患者的疗法，也许许多 其他免疫病理疾病。