Determining the compartmental role of B cell subsets during CNS autoimmunity

描述(由申请人提供)： B淋巴细胞是一种白血球，对外来蛋白包括感染提供免疫保护。然而，人们越来越认识到，B细胞免疫反应的异常也可能在人类炎症性疾病中发挥重要作用。多发性硬化症(MS)就是这样一种疾病，它是人类大脑和脊髓最常见的炎症性疾病，也是导致成年人神经功能障碍的第二大常见原因。最近的流行病学评估表明，每年有超过28,000名患有多发性硬化症(MS)的退伍军人在VA(http://www.va.gov/health/NewsFeatures/20110309a.asp).接受医疗护理全世界有250万被医生诊断为多发性硬化症的患者，也许迄今为止支持B细胞参与多发性硬化症发病机制的最好证据来自利妥昔单抗的临床试验，利妥昔单抗是一种耗尽血液和大脑中B淋巴细胞的药理学试剂。这方面的数据是由我的实验室公布的，并显示在这项拨款提案中。尽管人们认识到利妥昔单抗有利于多发性硬化症患者，但关于这种疾病中的B细胞的许多问题仍然没有答案。重要的是，目前尚不清楚大脑和脊髓中是否需要B细胞来增加MS疾病的负担，或者它们的作用是否仅限于中枢神经系统以外的器官。虽然B细胞可能会被利妥昔单抗耗尽，但在疾病的后期阶段，这些药物不太可能影响到大脑和脊髓中已经存在的所有B细胞。其他研究人员和我们小组最近的其他观察表明，并不是所有的多发性硬化症的B细胞都与疾病有关。一些B细胞似乎正在减少疾病的活跃度。我们将这些B细胞称为B调节细胞，将所有其他B细胞称为B调节细胞。我的实验室最近培育了一些小鼠，在这些小鼠中，B细胞无法迁移到大脑和脊髓。这些动物在其他方面发育正常。这些CD19Cre+/--4-整合素/f小鼠的产生为我们提供了一个独特的机会来阐明B细胞在中枢神经系统外和中枢神经系统内的作用。基于其他研究人员发表的工作，我们现在也能够产生不同类型的B调节性细胞和B非调节性细胞。基于我们的初步结果，并使用我的实验室生成的试剂，我们将检验关于B细胞亚群在实验性自身免疫性脑脊髓炎(EAE)MS动物模型中的作用的三种假说：a.我们假设B细胞亚群的产生对于改善早期CNS自身免疫性疾病是必需的；B.我们假设B非调节细胞向大脑和脊髓的迁移是维持EAE临床疾病活动的关键；理想情况下，一种假设是将在动物模型中进行的观察与患者中发生的事件联系起来。这可能是具有挑战性的，因为患者经常采取不同形式的治疗，这可能会影响免疫参数，包括身体不同隔室中细胞的数量和类型。为了避免这些错误的来源，我们将在第二阶段多国家随机双盲临床试验期间进行机械性研究，该试验由这项拨款提案的PI领导。这笔赠款的所有临床和影像研究都由一个单独的实体提供资金，并且 不是本申请的主题。这项临床试验将评估接受过FDA批准的药物Natalizumab治疗的患者。那他珠单抗可以防止包括B细胞在内的细胞迁移到大脑和脊髓。那他珠单抗将在所有患者中停用，他们将开始接受FDA批准的另一种治疗方法，格列普利(GA)，它可以诱导B调节细胞。基于我们的初步动物和人类数据，C.我们假设FDA批准的制剂Natalizumab阻止B调节细胞和B非调节细胞迁移到CNS；D.我们假设FDA批准的制剂GA促进多发性硬化症患者外周B调节细胞的产生，最终获得CNS。我们相信，我们的研究将大大增加我们对B细胞亚群作为疾病修饰物和MS患者潜在治疗剂的知识。

DESCRIPTION (provided by applicant): B lymphocytes are white blood cells that provide immunological protection against foreign proteins, including infections. However, it is increasingly being recognized that an aberration in immunological responses by B cells may also play an important role in human inflammatory disorders. One such disorder is multiple sclerosis (MS), which is the most common inflammatory disorder of the brain and spinal cord in humans, and which is the second most common cause of neurological disability in adults. Recent epidemiological assessments suggest that over 28,000 Veterans with multiple sclerosis (MS) receive medical care annually in VA (http://www.va.gov/health/NewsFeatures/20110309a.asp). World-wide, there are 2.5 million physician-diagnosed patients with MS. Perhaps the best evidence to date that support a role for B-cell involvement in MS pathogenesis come from clinical trials with rituximab in MS. Rituximab is a pharmacological agent that depletes B lymphocytes in the blood and the brain. Data in this regard was published by my laboratory and is shown in this grant proposal. Despite the recognition that rituximab benefits patients with MS, many questions regarding B cells in this disorder have remained unanswered. Importantly, it is currently unclear whether B cells are required in the brain and spinal cord to contribute to MS disease burden, or whether their role is limited to organs outside the central nervous system. While B cells may be depleted by rituximab, it is unlikely that these agents affect all B cells that are already in the brain and spnal cord during later stages of the disease. Other recent observations by other investigators and our group suggest that not all B cells in MS are contributing to disease. Some B cells appear to be diminishing disease activity. We refer to these B cells as B regulatory cells, and to all other B cells as B bon-regulatory cells. My laboratory recent has recently generated mice in which B cells cannot migrate into the brain and spinal cord. These animals are otherwise developmentally normal. The generation of these CD19.Cre+/--¿4-integrinf/f mice provides us a unique opportunity to clarify the role of B cells in compartments outside of the central nervous system and within it. Based on the published work by other investigators, we are also now able to generate different kinds of B regulatory cells and B non-regulatory cells. Based on our preliminary results, and using the reagents my laboratory has generated, we will test three hypothesis regarding the role of B cell subsets in the experimental autoimmune encephalomyelitis (EAE) animal model of MS: a. we hypothesize that the generation of B regulatory cells outside of the brain and spinal cord is required for amelioration of early stages of CNS autoimmune disease; b. we hypothesize that migration of B non-regulatory cells into the brain and spinal cord is critical in perpetuating EAE clinical disease activity; Ideally, one correlates observations made in an animal model with events that occur in patients. This can be challenging, as patients often take different forms of treatment that can affect immunological parameters, including the number and type of cells in different compartments of the body. To circumvent these sources of error, we will conduct mechanistic studies during a phase II multi-national randomized double-blind clinical trial that was initiated and is headed by the PI of this grant proposal. All clinical and imaging studies of this grant are funded by a separate entity, and are not subject of this application. The clinical trial will assess patients who have been treated with the FDA-approved agent natalizumab. Natalizumab prevents cells, including B cells, from migrating into the brain and spinal cord. Natalizumab will be discontinued in all patients, and they will be started on another FDA-approved therapy, glatiramer acetate (GA), which induces B regulatory cells. Based on our preliminary animal and human data, c. we hypothesize that the FDA-approved agent natalizumab prevents the migration of B regulatory cells and B non-regulatory cells into the CNS; d. we hypothesize that the FDA-approved agent GA promotes the generation of B regulatory cells in the periphery of patients with MS, which eventually will gain access to the CNS. We are confident that our studies will substantially increase our knowledge of B cell subsets as disease modifiers and as potential therapeutic agents in patients with MS.