Characterization of T cells in MOG antibody-associated disease

项目摘要/摘要 髓鞘少突胶质细胞糖蛋白(MOG)被认为是EAE和AS的自身抗原。 多发性硬化症可能的T细胞和抗体(Ab)靶点最近，MOG已被确认为几个中枢神经系统的靶点 自身免疫性疾病，包括急性播散性脑脊髓炎(ADEM)、视神经炎(ON)和 横贯性脊髓炎(TM)。这种谱系统称为MOG抗体相关疾病(MOGAD)。 目前，还没有FDA批准的MOGAD治疗方法。MOGAD发病机制的几个关键问题 目前还没有得到澄清。MOGAD中的MOG特异性抗体是T细胞依赖性的，在MOGAD中不是致病的 无T细胞介导的中枢神经系统炎症。因此，我们假设MOG特异性T细胞有一个 在MOGAD中发挥核心作用，并与B细胞，可能还有MOG特异性抗体合作，促进中枢神经系统损伤。 MOG诱导的EAE是评估MOG特异性T细胞如何与MOG-1协同作用的宝贵模型。 MOGAD中的特异性B细胞和抗体。与MOGAD类似，MOG诱导的EAE表现为ON、TM和 脑脊髓炎。除了作为MOG特异性抗体的来源外，B细胞还是抗原提呈细胞(APC)。EAE MOG蛋白的诱导是B细胞MHCⅡ依赖性的。B细胞抗原提呈是否促进发育 一种不同的致病T细胞谱系尚不清楚。我们假设B细胞抗原呈现扩增了一种独特的 MOG特异性致病T细胞的TCRA/b谱系。对MOG蛋白诱导的EAE的易感性 某些人类特有的氨基酸(AA)序列差异。新发现的MOG T细胞表位 研究的MOGAD患者位于AA序列差异聚集的区域内。至 了解细胞和体液对人类MOG的反应，并更好地翻译我们的发现，我们创建了 用人基因组MOG取代小鼠MOG基因组序列使MOG转基因小鼠人源化。 在这个项目中，我们建议：(1)鉴定和表征不同类型患者的MOG特异性T细胞。 MOGAD表型。外周血单个核细胞将从3岁以下登记的患者中采集 合作机构。MOG的特异性将通过重叠的MOG多肽的刺激来确定 TCRA/b谱系将通过单细胞RNA测序(scRNA-Seq)进行检测。(2)在次级目标2a中，我们将 确定体内B细胞抗原提呈如何影响致病的MOG特异性T细胞的发育 曲目。免疫野生型、B细胞缺陷和MOG特异性B细胞受体(BCR)小鼠的T细胞 使用MOG蛋白(B细胞依赖)或MOG肽(B细胞非依赖)将受到TCRA/b谱系的影响 经单链RNA-序列分析。在SubAim 2b中，我们的人源化MOG小鼠将被鉴定为MOG特异性T细胞 和体液反应，以及EAE中B细胞和T细胞协同作用的要求。中国人血清中MOG特异性抗体 MOGAD患者还将在受体人源化MOG小鼠身上进行致病潜力测试。 我们的结果应该提供关于MOGAD发病机制的宝贵知识和关于B- T在MOGAD和其他器官特异性自身免疫性疾病方面的合作。

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.