FC-RECEPTOR MEDIATED CELL-CELL INTERACTION IN ITP

该项目旨在表征和研究 血小板表面IgG的展示和亚类介导 包被抗体的识别、结合和破坏 血小板通过携带Fc受体的细胞。 该项目将有 三大研究成果。 在第一种方法中，将表征抗体的各种亚类， 它们介导Fc受体活性和相关性的能力将 进行临床观察。 致敏的正常血小板 将研究免疫性血小板减少症患者的体内 同样的。 在每种情况下，血小板上的IgG和IgG亚类 将使用单克隆125 I抗IgG测定对表面进行定量 在我们的实验室里开发的。 其次，亚类特异性抗血小板IgG抗体将被 从免疫性血小板减少症患者的血浆中纯化 患者使用免疫亲和层析技术。 将检测亚类特异性IgG组分的抗血小板 活动 这些IgG的血小板结合特性 亚类组分和Fc-受体介导的相互作用 在效应细胞和血小板之间， 将研究抗体。 最后，脾脏被认为是一个可能的来源， 抗血小板抗体的产生 血小板减少症 使用我们实验室开发的技术， 将进行研究，以识别，分离和培养 脾B淋巴细胞亚群（来自ITP患者）， 能够产生特异性抗血小板抗体。 这些 随后将使用特异性免疫B淋巴细胞， 构建能够连续 各种抗血小板单克隆抗体的生产 亚类特异性以及选择性抗原结合 特色 这些单克隆抗体将用于 Fc-受体相互作用的分析以及分离和 相关血小板膜抗原的表征。 因此，这些研究将提供有关以下方面的新信息： 调控人效应细胞Fc受体的分子机制 与血小板上的抗体相互作用， 与免疫血小板破坏的发病机制相关 综合征

This project is designed to characterize and study the ability of IgG display and subclass on the platelet surface in mediating recognition, binding and destruction of the antibody coated platelets by Fc-receptor bearing cells. This project will have three major research efforts. In the first, various subclasses of antibody will be characterized in their ability to mediate Fc-receptor activity and correlation will be made with clinical observations. Normal platelets sensitized in vivo from patients with immune thrombocytopenia will be studied similarly. In each case, IgG and IgG subclasses on the platelet surface will be quantified using a monoclonal 125I anti-IgG assay developed in our laboratory. Secondly, subclass specific anti-platelet IgG antibodies will be purified from plasma derived from immune thrombocytopenic patients using immunoaffinity chromatography techniques. Subclass specific IgG fractions will be tested for anti-platelet activity. The platelet binding characteristics of these IgG subclass fractions and the Fc-receptor mediated interaction between effector cells and platelets coated with these various antibodies will be studied. Finally, the spleen has been implicated as a possible source of anti-platelet antibody production in human immune thrombocytopenia. Using techniques developed in our laboratory, studies will be carried out to identify, separate and culture subsets of splenic B-lymphocytes (from ITP patients) that are capable of producing specific anti-platelet antibody. These specific immune B-lymphocytes will subsequently be used to construct human-human hybridomas capable of continuous production of monoclonal anti-platelet antibodies of various subclass specificities as well as selective antigen binding characteristics. These monoclonal antibodies will be used for analysis of Fc-receptor interaction as well as isolation and characterization of the relevant platelet membrane antigens. These studies will, thus, provide new information as regards with molecular mechanism controlling human effector cell Fc-receptor interaction with antibody on the platelet and will have direct relevance to the pathogenesis of immune platelet destruction syndromes.