Humoral Immunity, Astrocyte Injury, and Demyelination in Neuromyelitis Optica

描述（由申请人提供）：视神经肌萎缩症（NMO）是一种严重的人类脱髓鞘疾病，好发于视神经和脊髓。大约70%的受影响个体表现出针对水通道蛋白-4（AQP 4）水通道的血清自身抗体应答（NMO-IgG）。NMO-IgG与中枢神经系统（CNS）星形胶质细胞中的AQP 4结合被认为引发一系列炎症事件，包括补体和细胞介导的星形胶质细胞损伤、白细胞募集、细胞因子释放和髓磷脂损伤。使用单细胞流式细胞术和重组抗体技术，我们忠实地重建了NMO中的鞘内体液免疫应答，并证明AQP 4自身抗体足以引发星形胶质细胞损伤和疾病病理。为了进一步治疗人类脱髓鞘疾病患者，我们将使用我们的新资源和创新方法来解决我们对NMO发病机制的理解中的根本差距：1）在NMO中是否存在免疫应答的替代靶点？2)AQP 4免疫反应的性质与疾病的严重程度相关吗？3)在NMO病理学中，驱动星形胶质细胞损伤和髓鞘损伤的机制是什么？ 首先，为了确定NMO中自身免疫应答的新靶点，我们将检查非AQP 4特异性NMO重组抗体（rAbs）与人和鼠组织、神经胶质细胞系和原代神经胶质培养物的结合。候选rAb的概要将从我们现有的抗体库以及AQP 4血清阴性疾病的新病例中产生。其次，为了研究NMO-IgG特异性与临床疾病活动性之间的关联，我们将评估两种不同的AQP 4表位特异性模式与临床活动的频率和严重程度之间的关系。我们假设NMO-IgG中AQP 4表位特异性的谱将影响抗体效应子功能和CNS损伤。第三，我们将 使用疾病模型、转基因动物和NMO CSF rAbs的组合来定义AQP 4介导的星形胶质细胞损伤和髓鞘损伤的潜在机制。具体而言，我们将使用混合胶质细胞培养物、离体脊髓外植体和脑内注射来评估补体激活、抗体依赖性细胞介导的细胞毒性、兴奋性毒性、细胞因子释放和星形胶质细胞代谢对AQP 4抗体介导的CNS损伤的影响。详细描述NMO中的体液免疫应答将有助于NMO的诊断和治疗，人类脱髓鞘疾病中新靶抗原的鉴定，以及CNS炎性疾病中引起胶质细胞和神经元损伤的机制的阐明。

DESCRIPTION (provided by applicant): Neuromyelitis optica (NMO) is a severe human demyelinating disorder with predilection for the optic nerve and spinal cord. Approximately 70% of affected individuals demonstrate a serum autoantibody response, NMO-IgG, against the aquaporin-4 (AQP4) water channel. NMO-IgG binding to AQP4 in astrocytes in the central nervous system (CNS) is thought to initiate a series of inflammatory events, including complement- and cell-mediated astrocyte damage, leukocyte recruitment, cytokine release, and myelin damage. Using single- cell FACS and recombinant antibody technology, we have faithfully reconstructed the intrathecal humoral immune response in NMO and demonstrated that AQP4 autoantibodies are sufficient to initiate astrocyte injury and disease pathology. To further the care of patients with human demyelinating disease, we will use our novel resources and innovative approach to address fundamental gaps in our understanding of NMO pathogenesis: 1) Are there alternative targets of the immune response in NMO? 2) Does the nature of the AQP4 immune response correlate with disease severity? 3) What are the mechanisms driving astrocyte injury and myelin damage In NMO pathology? First, to identify novel targets of the autoimmune response in NMO, we will examine non-AQP4 specific NMO recombinant antibodies (rAbs) for binding to human and murine tissue, glial cell lines and primary glial cultures. A compendium of candidate rAbs will be generated from our existing antibody repertoires as well as new cases of AQP4 seronegative disease. Second, to investigate the association between NMO-IgG specificity and clinical disease activity, we will evaluate the relationship between two distinct patterns of AQP4 epitope specificity and the frequency and severity of clinical activity. We hypothesize that the spectrum of AQP4 epitope specificity in NMO-IgG will influence antibody effector function and CNS injury. And third, we will define the mechanisms underlying AQP4-mediated astrocyte injury and myelin damage using a combination of disease models, transgenic animals, and NMO CSF rAbs. Specifically, we will use mixed glial cultures, ex vivo spinal cord explants, and intracerebral injections to evaluate th effect of complement activation, antibody-dependent cell mediated cytotoxicity, excitotoxicity, cytokine release, and astrocyte metabolism on AQP4 antibody-mediated CNS injury. The detailed characterization of the humoral immune response in NMO will aid in the diagnosis and treatment of NMO, the identification of novel target antigens in human demyelinating disease, and the elucidation of the mechanisms causing glial and neuronal injury in CNS inflammatory disease.