Long-lived B cell Immunity in the Respiratory Tract

描述（由申请方提供）：呼吸道感染在局部诱导强烈和持久的体液免疫应答，显著促进免疫保护免受攻毒感染。诱导和控制保护性局部免疫反应的机制目前尚未完全了解。该研究基于小鼠的初步数据，这些数据表明，快速诱导的滤泡外病灶B细胞应答是流感病毒感染后呼吸道中长期体液免疫的来源。该提案的目的是确定调节呼吸道中流感病毒的这种长期局部抗体应答的机制。在特定目标#1中，将在野生型小鼠和缺乏生发中心形成的小鼠中测量流感病毒感染后肺抗体分泌细胞的分化途径和保护能力（SAP-/-小鼠）或强滤泡外病灶反应（灭活病毒递送后）使用BLIMP-1报告小鼠和新开发的用于追踪流感血凝素特异性的系统，离体表达C12 Id的B细胞。具体目标#2将研究调节肺浆细胞前体向呼吸道迁移/滞留的机制。他们将评估建立肺组织浆细胞库所需的病毒特异性B细胞/浆细胞从局部淋巴结迁移的程度，并使用遗传筛选和定制的微流体装置，将鉴定负责肺组织在剪切应力下浆细胞选择性积聚和/或保留的整合素和趋化因子/受体。具体目标#3将使用基因表达研究来确定肺组织中浆细胞/前体细胞的分化阶段，并使用BrDU标记研究来确定肺中抗体分泌细胞寿命的机制。连续转移研究将评估抗原和/或感染诱导的炎症信号维持的需要。这些研究将提供关于在呼吸道中产生长寿命体液免疫应答的特性和B细胞发育途径的新信息，关于B细胞应答调节的基本知识，可以帮助合理的疫苗设计。 公共卫生相关性：保护免受流感病毒感染至少部分是由流感病毒感染后在肺中建立的抗体分泌细胞贡献的。这项研究旨在了解这些细胞是如何产生的，以及是什么调节了它们在肺中的迁移/维持。这些基本信息将为旨在增强局部/粘膜免疫应答的合理疫苗设计提供潜在途径。

DESCRIPTION (provided by applicant): Respiratory tract infections induce strong and long-lasting humoral immune responses locally at the site, contributing significantly to immune protection from challenge infection. The mechanisms that induce and control protective local immune responses are currently not fully understood. The study is based on preliminary data in mice that implicate the rapidly induced extrafollicular foci B cell response as source for long-lived humoral immunity in the respiratory tract following influenza virus infection. The objective for this proposal is to identify the mechanisms that regulate this long-term local antibody response to influenza virus in the respiratory tract. In Specific Aim #1 the differentiation pathways and protective capacity of lung antibody-secreting cells following influenza virus infection will be measured in wildtype mice and in mice that lack formation of germinal centers (SAP-/- mice) or strong extrafollicular foci responses (following inactivated virus delivery) using BLIMP-1 reporter mice and a newly developed system for tracking of influenza hemagglutinin-specific, C12Id-expressing B cells ex vivo. Specific Aim #2 will study the mechanisms regulating the migration/retention of lung plasma cell precursors to the respiratory tract. They will assess the extent to which migration of virus-specific B cells/plasma cells from regional lymph nodes is required for the establishment of lung tissue plasma cell pools, and using genetic screening and a custom microfluidics device, will identify the integrins and chemokines/receptors responsible for the selective accumulation and/or retention of plasma cells the lung tissue under shear stress. Specific Aim #3 will use gene expression studies to determine the differentiation stage of plasma cells/precursors in the lung tissue and BrDU labeling studies to identify the mechanisms underlying the longevity of the antibody-secreting cells in the lung. Adoptive transfer studies will assess the requirements for antigen and/or infection-induced inflammatory signals for their maintenance. These studies will provide novel information on the characteristics and the B cell developmental pathways that generate the long-lived humoral immune responses in the respiratory tract, basic knowledge on B cell response regulation that can aid rationale vaccine design. PUBLIC HEALTH RELEVANCE: Protection from infections with influenza virus is contributed at least in part by antibody-secreting cells that establish in the lung following influenza virus infection. This study aims to understand how these cells are generated and what regulates their migration/maintenance in the lung. This basic information will provide potential avenues for rational vaccine design that aims to boost local/mucosal immune responses.