CELL ATTACHMENT AND INVASION BY TOXOPLASMA GONDII

弓形虫速殖子附着并进入所有有核细胞， 通过氧化和非氧化机制逃避死亡， 进入细胞后。本提案概述了我们对I.）的研究计划。 所选配体和受体参与速殖子附着于 细胞和II.）速殖子进入巨噬细胞的机制， 触发呼吸爆发，并驻留在所有细胞的空泡中， 既不酸化也不与溶体融合。 具体的计划我包括a.）补体作用的定义 速殖子细胞结合中的组分Clq，B.）表征 速殖子上细胞外基质蛋白层粘连蛋白的受体， 层粘连蛋白和宿主细胞受体在附着过程中的作用，以及 c.）鉴定涉及细胞的寄生虫中的顶端组分 约束力 II的具体计划包括调查a.）的相互作用 含T.弓形虫与其他细胞内 隔室，B.）速殖子吞噬作用的影响， 不同的受体对液泡组成和寄生虫的命运，c.） 吞噬细胞NADPH组分的掺入和功能活性 氧化酶系统在寄生液泡膜，d.）功能 纯化的寄生虫液泡的酸化分析，e.） 寄生虫空泡膜的免疫化学表征， 和f.）参与融合的细胞成分的功能分析 含溶酶体的寄生虫空泡。 这些研究，我们有大量的初步数据， 将研究T. 弓形虫，并将解决细胞生物学的关键问题， 细胞内融合和酸化事件。这些实验应该 定义这些事件中涉及的分子机制，并可能表明 干预战略。

Tachyzoites of Toxoplasma gondii attach to and enter all nucleated cells, evading killing by oxidative and non-oxidative mechanisms both during and after cell entry. This proposal outlines our plan for investigation of I.) selected ligands and receptors involved in attachment of tachyzoites to cells and II.) the mechanism by which tachyzoites enter macrophages without triggering a respiratory burst and reside in a vacuole in all cells which neither acidifies nor fuses with lyosomes. Specific plans for I include a.) definition of the role of complement component Clq in cell binding of tachyzoites, b.) characterization of receptors for the extracellular matrix protein laminin on tachyzoites and the role of laminin and host cell receptors in the attachment process, and c.) identification of apical components in the parasite involved in cell binding. Specific plans for II include investigation of a.) the interaction of parasitophorous vacuoles containing T. gondii with other intracellular compartments, b.) the influence of phagocytosis of tachyzoiters via different receptors on vacuole composition and of parasite fate, c.) incorporation and functional activity of components of the phagocyte NADPH oxidase system in the parasitophorous vacuole membrane, d.) functional analysis of acidification of purified parasitophorous vacuoles, e.) immunochemical characterization of the parasitophorous vacuole membrane, and f.) functional analysis of cell components involved in fusion of parasitophorous vacuoles with lysosomes. These studies, for which we have a substantial amount of preliminary data, will investigate important issues in cell attachment and entry by T. gondii, and will address critical issues in the cell biology of intracellular fusion and acidification events. Such experiments should define the molecular mechanisms involved in these events and may suggest strategies for intervention.