Regulation of B cells in the CNS

描述（由申请人提供）：在患有脱髓鞘疾病多发性硬化症（MS）的人和患有嗜神经性感染的人中，中枢神经系统（CNS）内抗体（Ab）的产生和B细胞的存在得到了充分的证明。他们在MS中的作用目前尚不清楚。然而，由于异位B细胞卵泡形成导致的持续免疫激活以及用抗CD 20单克隆抗体利妥昔单抗治疗以减少循环B细胞的MS患者的改善暗示了有害的体液应答。如果抗体与自身抗原交叉反应或直接靶向自身抗原，则抗体分泌细胞（ASC）也是有害的。相反，在病毒CNS感染期间，鞘内体液反应与保护功能相关。局部产生的抗病毒抗体与CNS内的持续免疫控制一致，没有明显的病理学，表明具有强效的非溶解性抗病毒作用。此外，委员会认为， 在类风湿性关节炎和MS的治疗过程中，在利妥昔单抗治疗后发生进行性多灶性白质脑病，从而使临床上不明显的持续存在的病毒失去控制的潜在危险变得明显。尽管体液免疫在神经炎症的不同环境中具有生物学意义，CNS中Ab的产生是如何持续的，以及哪些B细胞群和环境因素支持ASC的分化，仍然没有得到充分的表征。 该提案使用与脱髓鞘相关的急性和持续性感染的嗜神经冠状病毒模型来定义外周和CNS体液应答在支持CNS Ab产生中的相互作用。总体目标是扩大对MS等炎性疾病治疗选择的认识，而不会引起内源性病毒的出现，以及针对急性病毒性脑炎。有三个具体目标。目的1将明确外周淋巴组织来源的B细胞在补充和维持CNS内ASC中的作用。结果将揭示CNS内的所有B细胞是否都是生发中心衍生的，以及迁移到CNS的ASC是否在CNS内分化成长寿的ASC。此外，未探索的作用，非抗体产生记忆B细胞（B细胞）中枢神经系统的体液免疫将被定义。抗原（Ag）和CD4 T细胞在CNS内促进B细胞分化为无柄ASC中的作用将分别在目的2和3中确定。方法是基于转基因小鼠的免疫，其中通过荧光标记源自生发中心的B细胞以分离ASC和BclB用于过继转移。将在Ab产生缺陷的受体中监测其CNS迁移、分化和保护能力。通过供体B细胞特异性和炎症损伤的变化来检查同源Ag的影响。T细胞“帮助”将通过B CD4 T细胞消融和补充方法进行评估。这些结果将首次定义在人类自身免疫和CNS感染期间调节与B细胞相关的保护性和致病性应答的参数。

DESCRIPTION (provided by applicant): Antibody (Ab) production and the presence of B cells within the central nervous system (CNS) is well documented in humans with the demyelinating disease multiple sclerosis (MS) and those afflicted by neurotropic infections. Their role in MS is currently unclear. However, detrimental humoral responses are implied by ongoing immune activation due to ectopic B cell follicle formation, as well as improvement in MS patients treated with anti-CD20 monoclonal Ab rituximab to reduce circulating B cells. Antibody secreting cells (ASC) are also detrimental if Ab are cross-reactive with, or directly target, self antigens. By contrast, during viral CNS infections intrathecal humoral responses are associated with protective functions. Locally produced anti-viral Ab coincide with sustained immune control within the CNS without overt pathology implicating a potent non lytic anti-viral role. Furthermore, the potential danger of losing control of clinically inapparent persisting viruses became apparent by development of progressive multifocal leukoencephalopathy following rituximab treatment during therapy for rheumatoid arthritis and MS. Despite the biological significance of humoral immunity in diverse settings of neuroinflammation, how Ab production in the CNS is sustained and which B cell populations and environmental factors support differentiation of ASC remain poorly characterized. This proposal uses a neurotropic coronavirus model of acute and persistent infection associated with demyelination to define the interactions between peripheral and CNS humoral responses in supporting CNS Ab production. The overall goal is to broaden insights into treatment options for inflammatory diseases such as MS, without provoking emergence of endogenous viruses, as well as targeting acute viral encephalitis. Three Specific Aims are pursued. Aim 1 will define the contribution of peripheral lymphoid tissue derived B cells in replenishing and maintaining ASC within the CNS. Results will reveal whether all B cells within the CNS are germinal center derived, and whether ASC migrating to the CNS differentiate within the CNS to become long lived ASC. Furthermore, the unexplored role of non Ab producing memory B cells (Bmem) to CNS humoral immunity will be defined. The role of antigen (Ag) and CD4 T cells in promoting B cell differentiation to sessile ASC within the CNS will be determined in Aims 2 and 3, respectively. Approaches are based on immunization of transgenic mice in which germinal center derived B cells are marked by fluorescence to isolate ASC and Bmem for adoptive transfer. Their CNS migration, differentiation and protective capacity will be monitored in recipients defective in Ab production. The influence of cognate Ag is examined by variations in donor B cell specificities, and inflammatory insult. T cell "help" will be assessed b CD4 T cell ablation and supplementation approaches. The results will for the first time define the parameters regulating both protective and pathogenic responses associated with B cells during human autoimmunity and CNS infections.