Cooperation of CD8+ T cells and phagocytes to eliminate Toxoplasma cysts

CD8 T细胞和吞噬细胞合作消除弓形虫包囊

基本信息

批准号：
8414421
负责人：
YASUHIRO SUZUKI
金额：
$ 34.9万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-01-01 至 2016-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8414421
关键词：
Acquired Immunodeficiency Syndrome Acute Address Affect Animals Antigens Autophagocytosis Brain CD8-Positive T-Lymphocytes CD8B1 gene Cells Chronic Cyst Cytolysis Cytotoxic T-Lymphocytes Disease Effector Cell Encephalitis Epitopes Excision Genes Goals Histocompatibility Antigens Class I Hybridomas Immune Immune system Immunocompromised Host In Vitro Inbred BALB C Mice Individual Infection Interferons Knockout Mice Life Mediating Mediator of activation protein Methods Microglia Microscopy Molecular Mononuclear Mus Nitric Oxide Parasites Patients Peptides Phagocytes Pharmaceutical Preparations Play Process Production Research Project Grants Resistance Risk Role Staging Surface T-Lymphocyte Tissues Toxoplasma Toxoplasma gondii base cDNA Library cytotoxic human NOS2A protein in vitro Model in vivo killings macrophage novel perforin prevent public health relevance screening two-photon

项目摘要

DESCRIPTION (provided by applicant): Toxoplasma gondii establishes an important chronic infection capable of causing life-threatening toxoplasmic encephalitis in AIDS patients and other immunocompromised individuals. The basis of persistence of the infection is the tissue cyst, which remains largely quiescent for the life of the host, but can reactivate and cause disease. This stage of the parasite is not affected by any of the current drug treatments and it has been generally regarded as untouchable. However, our recent studies revealed that the immune T cells are able to eliminate T. gondii cysts from the brains of infected hosts when the T cells are transferred into infected immunodeficient animals that have already developed large numbers of the cysts. This T cell-mediated immune process is associated with accumulation of mononuclear cells, primarily microglia and macrophages morphologically, around tissue cysts. Since the accumulated phagocytes penetrate within the cyst, these cells appear to be the main effector cells that destroy the cysts and eliminate them from the brain after initiation of this process by immune T cells. CD8+ immune T cells possess a potent activity to initiate this anti-cyst immune process, and the protective activity of the T cells requires perforin. The overall goal of this research project is to determine the molecular mechanisms by which perforin-mediated activity of CD8+ immune T cells cooperates with the phagocytes to remove T. gondii cysts from the brain. In the first aim, we will determine if CD8+ immune T cells accumulate and attach to the cyst-containing cells in the brain. We will also determine if the CD8+ T cells lyse cyst-containing cells in a perforin-dependent manner in vitro and whether the perforin- mediated activity of CD8+ T cells induces the accumulation of phagocytes around the cysts in the brain. In the second aim, we will determine the MHC class I molecule(s) critical for recognition of cyst-containing cells by CD8+ T cells. We will then determine the T. gondii cyst epitope(s) presented by the identified MHC class I molecule for recognition by the CD8+ T cells by screening predicted bradyzoite epitope peptides and/or bradyzoite cDNA library. The third aim is to determine the mechanisms by which phagocytes eliminate T. gondii cysts after initiation of the immune process by CD8+ T cells. We will examine the roles of inducible nitric oxide synthase and autophagy in killing of bradyzoites and elimination of cysts using mice lacking a molecule required for each mechanism. The information generated from the studies in these three specific aims all together will provide the essential basis for developing a novel method(s) to activate CD8+ T cells and phagocytes to eliminate T. gondii cysts that can reactivate and cause toxoplasmic encephalitis.

描述（由申请人提供）：弓形虫Gondii建立了一种重要的慢性感染，能够在艾滋病患者和其他免疫功能低下的个体中引起威胁生命的毒质性脑炎。感染持续性的基础是组织囊肿，在宿主的生命中，它在很大程度上仍然是静止的，但可以重新激活并引起疾病。该寄生虫的这一阶段不受当前任何药物治疗的影响，通常被认为是不可动摇的。但是，我们最近的研究表明，当T细胞转移到已经发展大量囊肿的感染免疫缺陷的动物中时，免疫T细胞能够消除感染宿主的大脑的巨型囊肿。该T细胞介导的免疫过程与单核细胞的积累有关，主要是小胶质细胞和巨噬细胞在组织囊肿周围的形态学上。由于累积的吞噬细胞渗透到囊肿内，因此这些细胞似乎是破坏囊肿并在通过免疫T细胞开始后将其从大脑中消除的主要效应细胞。 CD8+免疫T细胞具有有效的活性来引发这种抗周期免疫过程，并且T细胞的保护活性需要穿孔。总体目标该研究项目的旨在确定CD8+免疫T细胞与吞噬细胞合作的分子机制，从而从大脑中去除T. gondii囊肿。在第一个目标中，我们将确定CD8+免疫T细胞是否积累并附着在大脑中的含囊肿细胞上。我们还将确定CD8+ T细胞在体外依赖性蛋白依赖性的含有囊肿的细胞以及CD8+ T细胞的穿孔蛋白介导的活性是否诱导大脑囊肿周围的吞噬细胞的积累。在第二个目标中，我们将确定MHC I类分子对CD8+ T细胞识别含囊肿细胞的至关重要。然后，我们将通过筛选预测的Bradyzoite表位肽和/或Bradyzoite CDNA库来确定由鉴定的MHC I类分子提出的T. gondii囊肿表位（S）识别CD8+ T细胞。第三个目的是确定吞噬细胞在通过CD8+ T细胞开始免疫过程后消除T. gondii囊肿的机制。我们将使用缺乏每种机制所需的分子的小鼠来检查诱导型一氧化氮合酶和自噬在杀死胸肌中的作用以及消除囊肿的作用。从这三个特定目的中，从研究中产生的信息将为开发一种新方法激活CD8+ T细胞和吞噬细胞的基本基础，以消除可以重新激活并引起弓形虫性脑炎的T. gondii囊肿。