FIBRONECTIN-IMMUNOGLOBULIN INTERACTION

纤维连接蛋白(FN)是一种高分子量的细胞表面和血浆 由离散的配体结合域(胶原蛋白， 纤维蛋白、肝素等)，调节各种生物活性。FN有 也被发现与冷冻球蛋白和免疫复合体(IC)有关。 我们的研究表明，主要的免疫球蛋白(Ig)类免疫球蛋白(Ig)的免疫球蛋白， IgM和IgA与FN的三个不同区域特异性结合 分子。检查生化性质和结构/功能 Fn/Ig相互作用的关系，我们计划确定主要的 Ig‘s和Fn中的结构，参与这种相互作用。这将是 通过两种方式完成：1)通过获得FN的蛋白水解性片段 以及保留其结合能力的免疫球蛋白，用于氨基酸测序。 2)在竞争性酶联免疫吸附试验中抑制FN与免疫球蛋白的相互作用 利用基因克隆的FN(类型I重复)的氨基酸序列 模块)以及Fn和Ig的合成肽。因为FN是一种调理素， Fn/Ig相互作用的意义在加速 从循环和沉积部位清除ICs。从… 从病理角度考虑，FN与Ig的相互作用可能是 参与免疫复合体疾病(ICD)的病因学研究，如 在许多骨髓增生性和自身免疫性疾病中观察到 炎症是由含有以下物质的组织中ICs的沉积引起的 Fn.我们计划将FN的结合相互作用(亲和力)与 正常的免疫球蛋白和冷冻球蛋白，通过酶联免疫吸附试验，确定是否最低 Ig复合体的聚集体大小可能影响ICs与Fn的结合。 将生成含有FN的细胞外基质(ECM)(去细胞 在细胞裂解后)，并用作体外模型来测试IC 结合；该系统应为IC提供体内相关性 组织中的沉积。Fn免疫球蛋白结合肽序列测定 通过结构研究，将被用来抑制IC与 ECM。有效的抑制将展示ECM FN(组织)的作用 在IC的隔离中，从而牵涉到FN的相互作用 Ig参与ICD的发病机制。FN与FN相互作用的研究 免疫球蛋白应提供对ICD病因的洞察并阐明 参与正常宿主免疫功能的机制。

Fibronectin (Fn) is a high molecular weight cell surface and plasma glycoprotein composed of discrete ligand binding domains (collagen, fibrin, heparin, etc) that mediate various biological activities. Fn has also been found associated with cryoglobulins and immune complexes (ICs). Our studies indicate that the major immunoglobulin (Ig) classes of IgG, IgM, and IgA specifically bind to three separate regions of the Fn molecule. To examine the biochemical nature and structure/function relationship of Fn/Ig interaction, we plan to determine the primary structure in both Ig's and Fn, involved in this interaction. This will be accomplished in two ways: 1) by obtaining proteolytic fragments of Fn and Igs, that retain their binding capacity, for amino acid sequencing. 2) by inhibiting the interaction of Fn with Igs in a competitive ELISA using genetically cloned amino acid sequences of Fn (type I repeat modules) and synthetic peptides of Fn and Igs. Because Fn is an opsonin, the significance of Fn/Ig interaction is implicated in accelerated clearance of ICs from the circulation and at sites of deposition. From a pathological consideration, the interaction of Fn with Ig may be involved in the etiology of immune complex disease (ICD), such as observed in many myeloproliferative and autoimmune disorders, where inflammation results from the deposition of ICs in tissues that contain Fn. We plan to compare the binding interaction (affinities) of Fn with normal Igs and cryoglobulins, by ELISA, and determine whether a minimum aggregate size of Ig complex may dispose the binding of ICs to Fn. Fn-containing extracellular matrices (ECM) will be generated (acellular following cell lysis) and used as an in vitro model to test for IC binding; this system should provide an in vivo correlate for IC deposition in tissues. The Ig-binding peptide sequence of Fn, determined by the structural studies, will be use to inhibit ICs from binding to the ECM. Effective inhibition would demonstrate a role for ECM Fn (tissue) in the sequestration of ICs and thereby, implicate the interaction of Fn with Ig in the mechanism of ICD. The study of the interaction of Fn with Ig should provide insight into the etiology of ICDs and elucidate mechanisms involved in normal host immune function.