INDUCTION OF TOLERANCE VIA DEC-205 ON DENDRITIC CELLS

树突状细胞是一种特化的抗原提呈细胞， 启动T细胞依赖的原位免疫。树突状细胞也可以 调节耐受，中心在胸腺，也许在外周 井。这个子项目将探讨树突状细胞潜在的 让T细胞沉默。我们将利用受体DEC-205，也就是 富含树突状细胞和某些上皮细胞。分离到DEC-205 并被克隆，具有DECalectin的结构。12月-205调解 涂层凹坑吸附兔抗DEC-205的研究 多囊内体，并有效地提呈特异性免疫球蛋白T 细胞。当大鼠抗DEC-205的mAb被注射到小鼠体内时，mAb靶向 树突状细胞，但一周内，T细胞对 大鼠免疫球蛋白在CFA中的免疫原性激发。 在这里，我们将通过体内DEC-205靶向多肽来确定组织 注射多肽的分布及其耐受活性。我们 假设胸腺耐受性会在以下情况下出现 髓质树突状细胞，可能还有皮质上皮，而 外周耐受性可能是由于靶向不成熟的亚群而形成的 或者通过给这些APC注入非常高剂量的 多肽。大鼠抗DEC-1耐受剂量要求和耐受时间 205将与以其他细胞和树突状细胞为靶点的大鼠单抗进行比较 细胞成分。一种与I-A/b结合并被识别的I-EA肽 将Y-Ae单抗偶联到抗DEC-205上，用于可视化 体内加工和靶向，以及对I-EA多肽的耐受性。 同样，流感HA多肽将与随后的抗DEC-205偶联 中央和外周T细胞在HA特异性TCR中的反应 转基因株系。 同时，我们将筛选一大批糖蛋白和 非糖化蛋白质通过DEC-205呈递并进行 DEC-205结构域的结构与功能分析 演示文稿。初步数据显示胎儿蛋白在DEC-205上的呈递 转染者。将评估体内糖蛋白耐受性。终于 骨髓和非骨髓中DEC-205基因缺失的影响 衍生的APC舱室将被记录在案。 因此，在本计划的背景下，我们将确定活动 DEC-205的配体，并测试是否通过这个靶向MHC II产物 受体为自身免疫干预提供了新的分子途径。 通过将自身抗原定位于APC的关键亚群，这种方法旨在 抑制I型糖尿病和其他疾病患者的致病T细胞 自身免疫性疾病。

Dendritic cells are specialized antigen presenting cells [APCs] for initiating T cell-dependent immunity in situ. Dendritic cells also can mediate tolerance, centrally in the thymus and perhaps peripherally as well. This subproject will approach the potential of dendritic cells to silence T cells. We will take advantage of a receptor, DEC-205, that is abundant on Dendritic and certain Epithelial Cells. DEC-205 was isolated and cloned, and has the structure of a DECalectin. DEC-205 mediates adsorptive uptake of rabbit anti-DEC-205 via coated pits and multivesicular endosomes, and efficient presentation to Ig-specific, T cells. When a rat mAb to DEC-205 is injected into mice, the mAb targets to dendritic cells but within a week, the T cells become tolerant to an immunogenic challenge of rat Ig in CFA. Here we will target peptides via DEC-205 in vivo to determine the tissue distribution of the injected peptide and its tolerizing activity. We hypothesize that thymic tolerance would ensue following presentation by medullary dendritic cells and possibly cortical epithelium, while peripheral tolerance may develop because of targeting to immature subsets of dendritic cells or by charging these APCs with very high doses of peptide. The dose requirements and duration of tolerance to rat anti-DEC- 205 will be compared with rat mAbs targeted to other cells and dendritic cell constituents. An I-Ea peptide that binds to I-A/b and is recognized by the Y-Ae mAb will be coupled to anti-DEC-205 and used to visualize processing and targeting in vivo, as well as tolerance to I-Ea peptide. Likewise an influenza HA peptide will be coupled to anti-DEC-205 to follow the response of central and peripheral T cells in HA-specific TCR transgenic lines. In parallel, we will screen a large panel of glycoproteins and nonglycosylated proteins for presentation via DEC-205 and carry out structure-function analyses of the DEC-205 domains that are involved in presentation. Preliminary data show presentation of fetuin by DEC-205 transfectants. Glycoprotein tolerance in vivo will be assessed. Finally the effects of the genetic deletion of DEC-205 in marrow and nonmarrow derived APC compartments will be documented. Within the context of this program, we will therefore identify active ligands for DEC-205 and test if targeting MHC II products via this receptor provides a new molecular approach for autoimmune intervention. By targeting autoantigens to critical subsets of APCs, this approach aims to silence disease-producing T cells in type I diabetes and other autoimmune diseases.