Characterization of T cells in MOG antibody-associated disease

项目总结/摘要 髓鞘少突胶质细胞糖蛋白（MOG）已被认为是EAE中的自身抗原（autoAg）， MS中的假定T细胞和抗体（Ab）靶标。最近，MOG已被鉴定为几种CNS中的靶标 自身免疫性疾病，包括急性播散性脑脊髓炎（ADEM）、视神经炎（ON），以及 横肌层（TM）。总的来说，该谱被称为MOG Ab相关疾病（MOGAD）。 目前，没有FDA批准的MOGAD治疗方法。MOGAD发病机制的主要方面 还没有被阐明。MOGAD中的MOG特异性抗体是T细胞依赖性的，并且在体内不是致病性的。 不存在T细胞介导的CNS炎症。因此，我们假设MOG特异性T细胞具有一种免疫调节作用。 在MOGAD中起中心作用，并与B细胞以及可能的MOG特异性Ab合作，以促进CNS损伤。 MOG诱导的EAE是评估MOG特异性T细胞如何与MOG协同作用的宝贵模型。 特异性B细胞和抗体。与MOGAD一样，MOG诱导的EAE表现为ON、TM和 脑脊髓炎除了作为MOG特异性Ab的来源之外，B细胞是Ag呈递细胞（APC）。EAE MOG蛋白诱导是B细胞MHC II依赖性的。B细胞Ag呈递是否促进发育 一个独特的致病性T细胞库是未知的。我们假设B细胞抗原呈递扩大了一个独特的 MOG特异性致病性T细胞的TCR a/B库。对MOG蛋白诱导的EAE敏感 某些人类特异性氨基酸（aa）序列差异。从大肠杆菌鉴定的新MOG T细胞表位 研究MOGAD患者位于许多氨基酸序列差异聚集的区域内。到 了解人类MOG的细胞和体液反应，并更好地翻译我们的发现，我们创建了 通过用人基因组MOG替换小鼠MOG基因组序列，人源化MOG敲入小鼠。 在这个项目中，我们提出：（1）识别和表征MOG特异性T细胞在不同的患者中， MOGAD表型。外周血单核细胞将从三个月后入组的患者中收集。 合作机构。MOG特异性将通过用重叠MOG肽刺激来确定 和TCR a/B库将通过单细胞RNA测序（scRNA-Seq）来检查。(2)在子目标2a中，我们将 确定体内B细胞Ag呈递如何影响致病性MOG特异性T细胞的发育 保留曲目。来自免疫的野生型、B细胞缺陷型和MOG特异性B细胞受体（BCR）小鼠的T细胞 MOG蛋白（B细胞依赖性）或MOG肽（B细胞非依赖性）将经受TCR a/B库 通过scRNA-Seq.在子目标2b中，我们的人源化MOG小鼠将表征MOG特异性T细胞亚群。 和体液免疫反应，以及EAE中需要B细胞-T细胞合作。血清MOG特异性Abs来自 还将在受体人源化MOG小鼠中测试MOGAD患者的致病潜力。 我们的研究结果应该提供关于MOGAD发病机制的宝贵知识和关于B- T细胞在MOGAD和其他器官特异性自身免疫性疾病中的协同作用

PROJECT SUMMARY / ABSTRACT Myelin oligodendrocyte glycoprotein (MOG) has been recognized as an autoantigen (autoAg) in EAE and as a putative T cell and antibody (Ab) target in MS. Recently, MOG has been identified as the target in several CNS autoimmune conditions, including acute disseminated encephalomyelitis (ADEM), optic neuritis (ON), and transverse myelitis (TM). Collectively, this spectrum is known as MOG Ab-associated disease (MOGAD). Currently, there are no FDA-approved treatments for MOGAD. Key aspects regarding MOGAD pathogenesis have not been elucidated. MOG-specific Abs in MOGAD are T cell-dependent and are not pathogenic in the absence of T cell-mediated CNS inflammation. Therefore, we hypothesize that MOG-specific T cells have a central role in MOGAD and cooperate with B cells, and possibly MOG-specific Abs, to promote CNS injury. MOG-induced EAE is an invaluable model to evaluate how MOG-specific T cells cooperate with MOG- specific B cells and Abs in MOGAD. Like MOGAD, MOG-induced EAE manifests as ON, TM and encephalomyelitis. Besides serving as a source of MOG-specific Abs, B cells are Ag presenting cells (APC). EAE induction by MOG protein is B cell MHC II-dependent. Whether B cell Ag presentation promotes development of a distinct pathogenic T cell repertoire is unknown. We hypothesize that B cell Ag presentation expands a unique TCRa/b repertoire of MOG-specific pathogenic T cells. Susceptibility to MOG protein-induced EAE is sensitive to certain human-specific amino acid (aa) sequence differences. Novel MOG T cell epitopes identified from studying MOGAD patients are located within the region where many aa sequence differences are clustered. To understand cellular and humoral responses to human MOG, and to better translate our findings, we created humanized MOG knock-in mice by replacing mouse MOG genomic sequence with human genomic MOG. In this program, we propose: (1) To identify and characterize MOG-specific T cells in patients with distinct MOGAD phenotypes. Peripheral blood mononuclear cells will be collected from patients enrolled at three collaborating institutions. MOG specificity will be determined by stimulation with overlapping MOG peptides and TCRa/b repertoire will be examined by single cell RNA sequencing (scRNA-Seq). (2) In subaim 2a we will determine how B cell Ag presentation in vivo may shape development of the pathogenic MOG-specific T cell repertoire. T cells from wild-type, B cell-deficient and MOG-specific B cell receptor (BCR) mice immunized with MOG protein (B cell-dependent) or MOG peptide (B cell-independent) will be subjected to TCRa/b repertoire analysis by scRNA-Seq. In subaim 2b, our humanized MOG mice will be characterized for MOG-specific T cell and humoral responses, and requirement for B cell-T cell cooperation in EAE. Serum MOG-specific Abs from MOGAD patients will also be tested for pathogenic potential in recipient humanized MOG mice. Our results should provide invaluable knowledge regarding MOGAD pathogenesis and insights regarding B- T cooperation in MOGAD and other organ-specific autoimmune diseases.