MOLECULAR MECHANISMS OF MHC LINKED SUSCEPTIBILITY

描述：(改编自申请人的摘要)-专业 组织相容性复合体(MHC)是慢性粒细胞白血病的重要易感基因 许多人类自身免疫性疾病。对寻常型天疱疮(PV)的敏感性， 一种皮肤的自身免疫性疾病，与MHC II类密切相关 等位基因在普通人群中很少见。在PV患者中， 针对角质形成细胞黏附分子桥粒蛋白3的自身抗体， 抑制桥粒芯糖蛋白3介导的角质形成细胞黏附 水泡的形成。MHC-II类基因的作用机制 对这种抗体介导的自身免疫疾病的易感性将进行研究。 在DQ1转基因小鼠模型和PV患者中。与光伏相关的 DQ1分子不同于常见的DQ1亚型 仅在DQβ链的单一位置(天冬氨酸氨基转移酶)对PV易感性 DQbeta57处的酸/缬氨酸)。这种疾病相关的多态导致了 负电荷进入DQ1肽结合部位。功能界别 DQ(Beta)57基因多态的后果将用可溶的 DQ1分子已在Drosphila Schneider细胞中表达。 来自桥粒芯糖蛋白3自身抗原的多肽与PV相关 将寻找DQ1分子，并研究DQ1多肽配体的致病性 将会被评估。 表达PV相关DQAlpha和DQbeta基因的转基因小鼠 (DQA1*0101，DQB1*0503)将作为PV的动物模型生成； 巴雷斯金(BSK)突变将被引入这些小鼠中，以允许视觉 对皮肤损伤的评估。为了确定该模型中的易感性 忠实地复制了人类疾病的基因，表达DQ1的小鼠 也将生成与PV不关联的子类型。DQ1 转基因小鼠将被用来定义DQ1多肽配体 皮肤自身免疫和确定哪个T细胞群(S)诱导 B细胞产生致病性自身抗体。NK1.1+T细胞是 特别感兴趣，因为它们是白介素4的主要来源 幼稚T细胞向Th2细胞分化的研究调查结果的相关性 在转基因小鼠模型中研究人类疾病的发病机制 被调查。将确定诱导的多肽(S)是否 转基因小鼠模型中的疾病被来自PV的T细胞识别 患者以及这些T细胞是否诱导桥粒芯糖蛋白3的产生 自身抗体。 这五个特定的目的是为了研究DQ1结合的相互作用 DQ1转基因小鼠中的多肽以及在PV患者中的研究。目标1是“为了 产生表达与PV相关的DQ1分子的转基因小鼠 将生成表示DQA1*0101和DQB1*0503以及控制 含有DQA1*0101和DQB1*0501的转基因动物。这将在#年完成。 已经剔除了MHC II类的动物(上标o/o)。在……里面 此外，巴雷斯金突变(BSK)也将进入这些动物体内 以便直接观察天疱疮的病变情况。 第二个具体目标是找到多肽的结构要求 与PV相关的DQ1分子结合并鉴定桥粒芯糖蛋白3 与DQ1结合的多肽。 构建，并将努力确定多肽的基序 与这个特定的II类分子结合的序列。可溶的 分子是在分子工程结合后产生的 α和β结构域相互连接，取代了跨膜结构域。 第三个具体目标是“研究自体免疫的诱导 桥粒芯糖蛋白3多肽和DQ1转基因小鼠。 具体目标四是研究NK1.1+/-T细胞和其他T细胞的作用 细胞亚群在诱导Th2介导的自身免疫应答中的作用 已计划进行细胞转移实验，以及使用 T细胞受体α链敲除小鼠。 第五个目标是“检查转基因研究结果的相关性”。 人类疾病发病机制的小鼠模型。 将开发特定的B细胞系以及T细胞系， 识别DQ1提出的桥粒芯糖蛋白3多肽。笔者希望通过这样的方式 重建T细胞克隆诱导桥粒粘连蛋白产生的系统 3自身抗体。在这个系统中将探索一些细胞因子。

DESCRIPTION: (Adapted from the applicant's abstract) - The major histocompatibility complex (MHC) is an important susceptibility locus for many human autoimmune diseases. Susceptibility to pemphigus vulgaris (PV), an autoimmune disease of the skin, is strongly associated with MHC class II alleles that are rare in the general population. In PV patients, autoantibodies against a keratinocyte adhesion molecule, desmoglein 3, inhibit desmoglein 3-mediated kearatinocyte adhesion and induce severe blister formation. The mechanisms by which MHC class II genes confer susceptibility to this antibody-mediated autoimmune disease will be studied in a DQ1 transgenic mouse model and in patients with PV. The PV-associated DQ1 molecule differs from a common DQ1 subtype that does not confer susceptibility to PV only at a single position of the DQbeta chain (aspartic acid/valine at DQbeta 57). This disease-associated polymorphism introduces a negative charge into the DQ1 peptide binding site. The functional consequences of the DQ(beta) 57 polymorphism will be examined using soluble DQ1 molecules that have been expressed in Drosphila Schneider cells. Peptides from the desmoglein 3 autoantigen that bind to the PV-associated DQ1 molecule will be sought, and the pathogenicity of DQ1 peptide ligands will be assessed. Transgenic mice that express the PV-associated DQalpha and DQbeta genes (DQA1*0101, DQB1*0503) will be generated as an animal model for PV; the bareskin (Bsk) mutation will be introduced into these mice to allow visual assessment of skin lesions. To determine if susceptibility in this model faithfully replicates the genetics of human disease, mice that express a DQ1 subtype that is not associated with PV will also be generated. DQ1 transgenic mice will be used to define the DQ1 peptide ligands that induce skin autoimmunity and to determine which T cell population(s) induce the production of pathogenic autoantibodies by B cells. NK1.1+ T cells are of particular interest because they are the major source of IL-4 for the differentiation of naive T cells into Th2 cells. The relevance of findings in the transgenic mouse model for the pathogenesis of the human disease will be investigated. It will be determined whether peptide(s) that induce disease in the transgenic mouse model are recognized by T cells from PV patients and whether these T cells induce the production of desmoglein 3 autoantibodies. The five specific aims are designed to study the interaction of DQ1-bound peptides in DQ1 transgenic mice and by studies in PV patients. Aim 1 is "to generate transgenic mice that express PV associated DQ1 molecule". Mice will be generated which express DQA1*0101 and DQB1*0503 and control transgenic animals with DQA1*0101 and DQB1*0501. This will be done in animals that have had the MHC class II knocked out (Ab superscript o/o). In addition, the bareskin mutation (Bsk) will also be moved into these animals so that the lesions of pemphigus can be directly observed. The second specific aim is to "find the structural requirements for peptide binding by the PV-associated DQ1 molecule and to identify desmoglein 3 peptides that are bound by DQ1." Peptide expression libraries will be constructed and an effort will be made to identify a motif for the peptide sequence which binds to this particular class II molecule. Soluble molecules have been generated after molecular engineering binding of the alpha and beta chains to one another in place of the transmembrane domains. A third specific aim is "to examine the induction of autoimmunity by desmoglein 3 peptides and DQ1 transgenic mice. Specific aim four is "to examine the role of NK1.1+/- T cells and other T cell subsets in the induction of a Th2-mediated autoimmune response against desmoglein 3." Cell transfer experiments are planned, as well as the use of T cell receptor alpha chain knock out mice. The fifth aim is "to examine the relevance of findings in the transgenic mouse model for the pathogenesis of the human disease." Here desmoglein 3 specific B cell lines will be developed as well as T cell lines that recognize desmoglein 3 peptides as presented by DQ1. The author hopes to reconstruct a system in which T cell clones induce production of desmoglein 3 autoantibodies. A number of cytokines will be explored in this system.