Sjogren's Syndrome Pathogenic Autoantibodies

项目总结/摘要 舍格伦综合征（SS）是一种全身性自身免疫性疾病，最常见的目标是外分泌 该疾病的特征是持续性眼、口干燥以及腺体外受累。唾液 腺体淋巴细胞浸润是该疾病的病理学发现。有B细胞扩张，超- SS患者外分泌腺的反应性和抗体形成。部分患者有腺性异位 生发中心的形成，以及II型B细胞（T2）的存在，表型类似于边缘 脾中的MZ区（B细胞）作为缺失的检查点，在诱导/丧失 宽容患者血清通常含有针对Ro（SS-A）和La（SS-B）的自身抗体，并且抗Ro（SS-A）和抗La（SS-B）的抗体的数量在患者血清中增加。 唾液浸润中抗Ro和抗La特异性B细胞与血清中抗体滴度相关。其他 存在特异性，包括对毒蕈碱3受体（M3 R）的特异性。有证据表明 靶向在副交感神经信号传导中重要的M3 R的抗体可诱导腺体功能障碍。我们也这么想 其他人已经证明，当将来自受影响个体的IgG注射到幼稚小鼠中时， 表现为唾液流障碍的疾病。因此，证据有力地支持了B 浸润SS患者唾液腺的细胞不仅产生自身抗体， 腺体功能障碍，但也是血清中某些自身抗体的来源。这项提案将考验 假设是这种情况，并将解决这种功能障碍的致病机制。在 目的1、利用最新的尖端技术，对V-region进行测序， 唾液腺浆母细胞的自身抗体（mAb），并将其与 相同患者的血清，使用高分辨率Orbitrap质谱IG蛋白测序。 因此，我们将确定循环中的抗Ro抗体是否是由外周血中的抗体分泌细胞产生的。 唾液腺鉴于抗Ro克隆型定期更替，确定这种更替涉及 外分泌腺中的B淋巴细胞将是了解该疾病发病机制的重要线索。我们 已经证明，一些患者有克隆扩增的B细胞浸润腺体，而其他患者 不要。在目标2中，我们将确定克隆扩增的B细胞浸润的相关性和病理生理学。 唾液腺我们假设克隆扩增的B细胞与其他免疫学相关。 腺体的特征，并可能识别驱动生发中心的种群或微环境影响 形成、B细胞增殖和自身抗体产生。我们手头有SS mAb，可以结合并阻断M3 R 激活，因此可能参与疾病的发病机制。在目标3中，我们将定义 阻断唾液流的致病性mAb，并确定它们是否可以被抑制。我们假设 与非致病性mAb相比，致病性mAb将结合不同的M3 R表位， 表位作为反向D-氨基酸肽将在我们的小鼠模型中具有阻断作用。

Project Summary/Abstract Sjögren's syndrome (SS) is a systemic autoimmune disease that most commonly targets the exocrine glands and is characterized by persistent dry eyes and mouth as well as extra-glandular involvement. Salivary gland lymphocytic infiltrates are a pathological finding in the disease. There are B cell expansions, hyper- reactivity and antibody formation in exocrine glands of SS patients. Some patients have glandular ectopic germinal center formation, as well as the presence of Type II B cells (T2) phenotypically similar to marginal zone (MZ) B cells in the spleen serving as a checkpoint for deletion and are important in the induction/loss of tolerance. Patient serum commonly contains autoantibodies to Ro (SS-A) and La (SS-B), and the number of anti-Ro and -La specific B cells in salivary infiltrates correlate with antibody titer in the serum. Other specificities are present, including those towards muscarinic 3 receptor (M3R). The evidence suggests antibodies targeting M3R, important in para-sympathetic signaling, may induce glandular dysfunction. We, and others have demonstrated that IgG from affected individuals, when injected into naïve mice, can transfer disease as manifested by salivary flow impairment. Thus, the evidence strongly supports the premise that B cells infiltrating the salivary glands of SS patients not only make autoantibodies that are in part responsible for glandular dysfunction but are also a source of some autoantibodies in the sera. This proposal will test the hypothesis that this is the case, and will address the pathogenic mechanisms underlying this dysfunction. In Aim 1, using the latest cutting-edge techniques, we will sequence the V-regions and produce monoclonal antibodies (mAb) from salivary gland plasmablasts, and compare them to the autoantibody repertoire found in the serum of the same patients, using high-resolution Orbitrap mass spectrometric Ig protein sequencing. Thus, we will determine whether anti-Ro in the circulation is produced by antibody-secreting cells in the salivary glands. Given that anti-Ro clonotypes are turned over regularly, determining that this turnover involves the B lymphocytes in the exocrine glands will be an important insight into the pathogenesis of the disease. We have demonstrated that some patients have clonally expanded B cells infiltrating the gland, while other patients do not. In Aim 2 we will determine the correlates and pathophysiology of clonally expanded B cells infiltrating the salivary glands. We hypothesize that clonally expanded B cells will be related to other immunological features in the gland and may identify populations or microenvironmental influences that drive germinal center formation, B cell proliferation and autoantibody production. We have in hand SS mAb that bind and block M3R activation, and thus, may be involved in the pathogenesis of the disease. In Aim 3 we will define the nature of pathogenic mAbs that block salivary flow, and determine if they can be inhibited. We hypothesize that pathogenic mAb will bind distinct M3R epitopes compared to non-pathogenic mAb and representation of the epitope as an inverse D-amino acid peptide will have a blocking action in our mouse model.