ALTERED N-LINKED OLIGOSACCHARIDES ON IGG IN RHEMATOID ARTHRITIS

慢性炎症反应导致滑膜破坏 组织是类风湿性关节炎(RA)的特征，这是一种自身免疫性疾病 病因不明的疾病。关节中的树突状细胞很可能 通过提供多肽在疾病的始发过程中发挥关键作用 从自身蛋白质到自身反应性T细胞的抗原。我们 观察到树突状细胞对免疫球蛋白的摄取增加 改变的N-寡糖，以前显示存在于 类风湿关节炎患者的血清和滑液。这表明 树突状细胞摄取的修饰免疫球蛋白(G0)可能是 通过II类组织相容性蛋白进行加工和呈递 有效，导致T细胞反应性耐受性崩溃 用免疫球蛋白衍生的多肽。要进一步表征G0的结合 免疫球蛋白结合树突状细胞，检测免疫球蛋白反应性T细胞是否 造成疾病，我们将执行以下操作 实验。在具体目标1中，将开发新的分析方法 这为检测G0的结合提供了一种高度敏感的手段 免疫球蛋白结合树突状细胞。Ig G同种类型也将作为一种 约束的决定因素。内化GO的亚细胞定位 免疫球蛋白将使用电子显微镜进行测定，并与 G0免疫球蛋白与II类免疫球蛋白的相容处理途径 使用生化分析进行评估。在《特定目标2》中，受体 负责结合G0免疫球蛋白的树突状细胞表面将 化学交联法和凝胶电泳法鉴定 分析。在特异靶3中，患者和正常人的T细胞 将测试对照组对树突状细胞的增殖反应 用G0免疫球蛋白冲击。这些实验应该确定G0 树突状细胞摄取的免疫球蛋白可以有效地处理和 通过第二类组织相容性分子呈递给外周T细胞 潜在的自体反应的细胞。

Chronic inflammatory responses leading to destruction of synovial tissue is characteristic of rheumatoid arthritis (RA), an autoimmune disease of unknown etiology. Dendritic cells in the joint are likely to play a crucial role in initiating the disease by presenting peptide antigens derived from self proteins to autoreactive T cells. We have observed increased uptake by dendritic cells of IgGs bearing altered N-oligosaccharides, shown previously to be present in the serum and synovial fluid of RA patients. This suggests that modified IgG (G0 IgG) taken up by dendritic cells may be processed and presented via class II histocompatibility proteins quite efficiently, leading to a breakdown in tolerance of T cells reactive with IgG-derived peptides. To further characterize binding of G0 IgG to dendritic cells and test whether IgG-reactive T cells might contribute to the disease, we will perform the following experiments. In specific aim 1, novel assays will be developed which provide a highly sensitive means of detecting binding of G0 IgG to dendritic cells. IgG isotype will also be tested as a determinant of binding. Subcellular localization of internalized Go IgG will determined using electron microscopy, and intersection of G0 IgG with the class II h istocompatibiity processing pathway assessed using biochemical assays. In specific aim 2, receptors on the surface of dendritic cells responsible for binding G0 IgG will be identified using chemical crosslinking and gel electrophoretic analyses. In specific aim 3, T cells from patients and normal controls will be tested for proliferative responses to dendritic cells pulsed with G0 IgG. These experiments should determine if G0 IgG taken up by dendritic cells can be efficiently processed and presented via class II histocompatibility molecules to peripheral T cells which are potentially autoreactive.