Definition of follicular stromal cell subset interactions with B cells

滤泡基质细胞亚群与 B 细胞相互作用的定义

• 批准号: 8492703
• 负责人: ANN M HABERMAN
• 金额: $ 8.31万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8492703
• 关键词: Activated Lymphocyte; Adjuvant; Antigens; Architecture; Area; Asses; B-Lymphocytes; Behavior; Blood; Bone Marrow; Cell Communication; Cells; Cellular Morphology; Chimera organism; Collection; Complex; Dendrites; Endothelial Cells; Environment; Event; Fingerprint; Follicular Dendritic Cells; Histology; Immune response; Immunization; In Situ; Laser Scanning Microscopy; Lymph; Lymph Node Subcapsular Sinus; Lymphocyte; Lymphocyte antigen; Lymphoid Tissue; Mediating; Morphology; Movement; Mus; Neighborhoods; Pericytes; Positioning Attribute; Relative (related person); Research Infrastructure; Reticular Cell; Role; Signal Transduction; Stromal Cells; Structure; Synapses; T-Lymphocyte; Testing; Time; Tissues; Vaccines; ameboid movement; base; cell motility; cell type; chemokine; chemokine receptor; intravital imaging; intravital microscopy; notch protein; pathogen; public health relevance; receptor expression; reconstruction; research study; response; two-photon

DESCRIPTION (provided by applicant): The initiation of immune responses within lymphoid tissue involves a carefully orchestrated movement of activated lymphocytes within an elaborate network of stationary stromal cells. Lymphoid tissue architecture is comprised of distinguishable microanatomic "neighborhoods" that are based on a complex arrangement of stromal cells. Due to the secretion of distinctive combinations of chemokines by stromal cell subsets, the chemokine fingerprint within B cell follicles is distinguishable from its neighboring T cell zone. Through shifts in chemokine receptor expression after activation, antigen engaged B and T cells reposition themselves to congregate within new niches, promoting their cognate encounters and enabling key steps in the differentiation of critical effectors. Although on a macro scale, the uniform distribution of na¿ve B cells throughout the follicle might suggest a similar uniformity in the stationary structural underpinnings, there are instead many stromal cell subsets positioned within follicles. In addition to the well characterized follicular dendritic cell (FDC), B cell folicles also harbor lymph and blood endothelial cells, the later covered by pericytes. Fibroblastic reticular cells rim the inside edge of the border of the follicle closest to the T cell zone, wheres the subcapsular sinus lining is a collection of yet more cell types including a marginal reticular cell with descending dendrites. Despite the critical role of stromal cells in defining the landmark for lymphocyte orientation during initial activation events, many fundamental aspects of B cell interactions with follicular stroma are unknown. Here we propose to examine the interactions between B cells and the stromal cell subsets that make up the follicular infrastructure. Aim 1: Define the stromal cell framework of B cell follicles. Using intravital microscopy of fluorescent bone marrow chimeras, the relative positioning of blood and lymph vessels vis-¿-vis FDCs and other intra-follicular stromal cells will be defined. We will assess the consistency of their juxtapositions, spacing and associated cell types before and after immunization. Aim 2: Define the propensity of na¿ve and activated B cells to interact with stromal cell subsets via intravital microscopy. The morphodynamics and mode of propulsion between B cells in contact with stroma will be compared to those within regions that lack stroma, and the impact of blood or lymph-borne antigen/adjuvants on this behavior determined. Motility parameters of na¿ve and activated B cells within stromal gaps will be quantified to test the hypothesis that such movement is transient and a directed shift from one stromal contact to another. Aim 3: Examine B cells in situ for intracellular indicators of potential signaling events during contacts with strmal cell subsets. B cells with synaptic morphology adjacent to stromal cells will be examined by histology for intracellular indicators of Notch, BMP and BCR mediated signaling coincident with stromal cell subset contacts. To test the hypothesis that such contacts support BCR derived tonic signaling, we will perform intravital imaging of B cells transfected with a NFAT-eGFP retroviral construct within LNs of fluorescent BM chimeras.

描述（由申请人提供）：淋巴组织内免疫反应的启动涉及活化淋巴细胞在复杂的静止基质细胞网络内精心策划的运动，淋巴组织结构由基于复杂排列的可区分的微观解剖“邻域”组成。由于基质细胞亚群分泌独特的趋化因子组合，B 细胞滤泡内的趋化因子指纹与其邻近的 T 细胞不同。通过激活后趋化因子受体表达的变化，抗原结合的 B 细胞和 T 细胞重新定位以聚集在新的生态位中，促进它们的同源相遇并实现关键效应细胞分化的关键步骤。呐整个卵泡中的 ve B 细胞可能表明在 除了固定的结构基础外，滤泡内还存在许多基质细胞亚群，除了特征明确的滤泡树突状细胞 (FDC) 外，B 细胞滤泡还含有淋巴和血液内皮细胞，后者被周细胞覆盖。最靠近 T 细胞区域的卵泡边界的内边缘，其中囊下窦内壁是更多细胞类型的集合尽管基质细胞在初始激活事件期间定义淋巴细胞定向的标志中发挥着关键作用，但 B 细胞与滤泡基质相互作用的许多基本方面尚不清楚。细胞和构成滤泡基础设施的基质细胞亚群 目标 1：使用荧光骨髓嵌合体的活体显微镜确定 B 细胞滤泡的基质细胞框架。血管和淋巴管的相对位置 vis-¿ -将定义 FDC 和其他滤泡内基质细胞，我们将评估免疫前后它们并置、间距和相关细胞类型的一致性。 ve 和活化的 B 细胞通过活体显微镜与基质细胞亚群相互作用。与基质接触的 B 细胞之间的形态动力学和推进模式将与缺乏基质的区域内的 B 细胞进行比较，以及血液或淋巴携带的抗原/的影响。佐剂对这种行为的运动参数进行了测定。基质间隙内的 ve 和活化的 B 细胞将被量化，以检验这种运动是短暂的以及从一种基质接触到另一种基质接触的定向转变的假设。 目标 3：原位检查 B 细胞，以了解与基质接触期间潜在信号事件的细胞内指标。具有与基质细胞相邻的突触形态的细胞亚群将通过组织学检查与基质细胞亚群接触一致的Notch、BMP和BCR介导的信号传导的细胞内指标。这种接触支持 BCR 衍生的强直信号传导，我们将对荧光 BM 嵌合体 LN 内用 NFAT-eGFP 逆转录病毒构建体转染的 B 细胞进行活体成像。