INTRACELLULAR SURVIVAL BY TOXOPLASMA

弓形虫的细胞内存活

• 批准号: 2069112
• 负责人: L. David Sibley
• 金额: $ 19.94万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2069112
• 关键词: SDS polyacrylamide gel electrophoresis; Toxoplasma; Toxoplasma gondii; antibody receptor; antigen presentation; calcium; cell fusion; cell membrane; enzyme linked immunosorbent assay; fluorescence microscopy; host organism interaction; immunoelectron microscopy; intracellular parasitism; membrane activity; membrane proteins; monoclonal antibody; phagocytosis; protozoal antigen; secretory protein; vesicle /vacuole; video recording system; western blottings

The success of Toxoplasma gondii as an intracellular parasite is dependent on its unique ability to invade and survive within virtually any nucleated cell in a wide range of vertebrate hosts. Upwards of 50% of the world's human population is chronically infected with Toxoplasma, although these infections are normally asymptomatic. The emergence of toxoplasmosis as a major opportunistic pathogen in pregnancy and AIDS, has necessitated a greater understanding of the unique adaptations for intracellular survival employed by this parasite. The proposed project provides a comprehensive analysis of the parasitophorous vacuole occupied by Toxoplasma which forms a protective interface that is key to intracellular survival. We have developed in vitro systems to examine the composition and kinetics of vacuole development with respect to models for normal phagocytosis. This comparative approach will be used to identify the biochemical basis of the resistance to fusion by Toxoplasma-containing vacuoles. To explore the active modification of this compartment by the parasite, we have characterized the secretion of two prominent proteins that reside in the mature vacuole (GRA2 and NTPase). Our preliminary findings indicate an important role for intracellular calcium in regulating the secretion of parasite proteins within the vacuole. We will examine this regulation in detail and explore the feasibility of using pharmacological agents that disrupt calcium homeostasis to block secretion and effect intracellular survival. Finally, we will identify new parasite secretory proteins that are targeted to the vacuole membrane to expand our understanding of the unique modifications of this compartment. These findings will provide key information about the composition of the parasitophorous vacuole that may provide a means of targeting intracellular parasites for destruction. The information gained here is also directly relevant to understanding antigen processing and presentation for immunological intervention and may provide a rational approach for targeted delivery of drugs to the parasitophorous vacuole.

弓形虫作为细胞内寄生虫的成功是 依赖于其独特的入侵能力并在虚拟环境中生存 多种脊椎动物宿主中的任何有核细胞。 50% 以上 世界人口长期感染弓形虫， 尽管这些感染通常是无症状的。 的出现 弓形体病是妊娠和艾滋病中的主要机会病原体， 需要对独特的适应性有更深入的了解 这种寄生虫利用细胞内生存。 拟议项目 提供对寄生液泡占据的全面分析 由弓形虫形成的保护界面是关键 细胞内存活。 我们开发了体外系统来检查 液泡发育的组成和动力学 正常吞噬作用模型。 将使用这种比较方法 确定融合抗性的生化基础 含有弓形虫的液泡。 探索主动改造 寄生虫的这个隔室，我们已经表征了其分泌 成熟液泡中存在两种重要的蛋白质（GRA2 和 NTP酶）。 我们的初步研究结果表明， 细胞内钙调节寄生虫蛋白的分泌 液泡内。 我们将详细审查该规定并 探索使用破坏药物的可行性 钙稳态以阻止分泌并影响细胞内存活。 最后，我们将鉴定新的寄生虫分泌蛋白 针对液泡膜以扩大我们对液泡膜的理解 该隔间的独特修改。 这些发现将提供 有关寄生液泡组成的关键信息 可能提供一种针对细胞内寄生虫进行破坏的方法。 这里获得的信息也与理解直接相关 用于免疫干预的抗原加工和呈递 可能为靶向递送药物提供合理的方法 寄生泡。