Pathogenic B cell:CD4 T cell interactions in a novel B cell-dependent EAE mouse model of multiple sclerosis

项目摘要 MS是一种免疫介导的中枢神经系统脱髓鞘疾病，尽管一线药物 限制症状，疾病会随着时间的推移而发展，并且是无法治愈的。鉴于它的早期发病和在 多发性硬化症的流行给近100万美国人带来了巨大的健康和经济负担 关于美国的。鉴于B细胞耗竭治疗(BCDT)的成功，理解 B细胞在疾病中的致病作用引起了人们的高度关注。由于CD20的靶向性 在BCDT中，人们了解到B细胞通过其他机制参与MS病理 抗体的产生，可能是通过自身反应性的CD4T细胞的支持。大多数动物模型 MS(实验性自身免疫性脑脊髓炎或EAE)是B细胞非依赖性的，这限制了 对体内致病性B：T相互作用的影响洞察力。为了规避这一点，我们最近 建立一种以CD4T细胞为特征的B细胞依赖、抗体非依赖的多发性硬化动物模型 对高度丰富和100%的胞外区序列的免疫反应性 保守的髓鞘蛋白脂蛋白(PLPECD)。通过严格的初步研究，我们有 发现B细胞介导的抗原通过MHC II类递呈给CD4是必要的 PLPECD诱导的EAE中B细胞的致病机制，其中B细胞通过 与非B细胞抗原提呈细胞相比，在处理和 将PLPECD内的免疫优势残基呈现给PLP178-191反应的CD4T细胞。 进一步模仿多发性硬化症的持续致病B细胞参与，与B细胞不同- 由PLP178-191驱动的独立EAE，BCDT有力地改善了已建立的PLPECD疾病。 B细胞在神经炎性反应中支持CD4的作用及对T辅助细胞多样性的影响 (Th)在MS中观察到的轮廓仍不清楚。了解多发性硬化症的这些动态可能会证明 在确定哪些患者会对BCDT有反应从而建立致病B细胞模型方面具有重要意义 参与体内活动正变得越来越重要。我们的目标是用这个强大的B 细胞依赖型EAE模型以了解B细胞如何塑造CD4应答并研究 中枢神经系统中B细胞对CD4的支持。这些是B细胞介导的病理学的关键方面 目前还不清楚，也很难在体内进行适当的建模。我们的模特把我们放进了 一个独特的位置来回答这些问题。我们假设B细胞提供的细胞因子 有偏见的Th谱和CNS B细胞：CD4相互作用在促进脱髓鞘中起关键作用 在PLPECD EAE中。特定目标1将通过测试确定B细胞如何形成致病的CD4T细胞 B细胞提供的细胞因子对Th1/17偏向的影响。特定目标2将确定CNS B细胞的作用 在PLPECD诱导的EAE中，观察B细胞支持的神经炎症。

PROJECT ABSTRACT MS is an immune-mediated demyelinating disease of the CNS, and despite first line drugs that limit symptoms, disease progresses over time and is incurable. Given its early onset and rise in prevalence for nearly 1 million Americans, MS presents immense health and economic burdens on the United States. Given the success of B cell depletion therapy (BCDT), understanding the pathogenic roles of B cells during disease is of high interest. Because of the CD20-targeted nature of BCDT, it is understood that B cells contribute to MS pathology through mechanisms beyond antibody production, likely through support of autoreactive CD4 T cells. Most animal models of MS (experimental autoimmune encephalomyelitis or EAE) are B cell-independent, which limits impactful insights into pathogenic B:T interactions in vivo. To circumvent this, we have recently developed a B cell-dependent, antibody-independent animal model of MS featuring CD4 T cell immunoreactivity to the extracellular domain sequences of the highly abundant and 100% conserved myelin proteolipid protein (PLPECD). Through rigorous preliminary studies, we have identified B cell-mediated antigen presentation to CD4s through MHC class II as the required pathogenic B cell mechanism in PLPECD-induced EAE, where B cells engage PLPECD through the B cell receptor and are superior vs. non-B cell antigen presenting cells at processing and presenting immunodominant residues from within PLPECD to PLP178-191-reactive CD4 T cells. Further mimicking the sustained pathogenic B cell involvement seen in MS and unlike B cell- independent EAE driven by PLP178-191, BCDT robustly ameliorates established PLPECD disease. B cells’ role in supporting CD4s during neuroinflammation and shaping the diverse T helper cell (Th) profiles observed in MS remains unclear. Understanding these dynamics in MS may prove significant in identifying which patients will respond to BCDT and thus modeling pathogenic B cell involvement in vivo is becoming increasingly important. Our objective is to use this powerful B cell-dependent EAE model to understand how B cells shape the CD4 response and to investigate B cell-mediated support of CD4s in the CNS. These are key aspects of B cell-mediated pathology that are not currently understood and difficult to model appropriately in vivo. Our model put us in a unique position to answer these questions. We hypothesize that B cell-provided cytokines shape a biased Th profile and that CNS B cell:CD4 interactions are critical in promoting demyelination in PLPECD EAE. Specific Aim 1 will determine how B cells shape pathogenic CD4 T cells by testing B cell-provided cytokines’ impact on Th1/17 bias. Specific Aim 2 will determine CNS B cells’ role in PLPECD-induced EAE and visualize B cell-supported neuroinflammation.