B cell presentation of antigen to CD4 T follicular helper cells

B 细胞将抗原呈递给 CD4 T 滤泡辅助细胞

• 批准号: 8606816
• 负责人: Andrea Janine Sant
• 金额: $ 23.03万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8606816
• 关键词: Affinity; Antibody Formation; Antigen Presentation; Antigen Targeting; Antigen-Presenting Cells; Antigens; Autoimmune Diseases; B cell repertoire; B-Lymphocyte Epitopes; B-Lymphocytes; Bacteria; Binding; Biological Assay; Biological Models; CD4 Positive T Lymphocytes; Cell Communication; Cells; Dendritic Cells; Development; Engineering; Ensure; Epitopes; Event; Experimental Models; Flow Cytometry; Future; Genetic; Genetic Models; HIV; Helper-Inducer T-Lymphocyte; Immune response; Immunity; Immunoglobulins; Influenza; Interferon Type II; Ligands; Lymphocyte Subset; Lymphoid Tissue; Mediating; Methods; Modeling; Molecular; Mus; Peptide Hydrolases; Peptides; Process; Production; Proteins; Receptors, Antigen, B-Cell; Role; Specificity; Testing; Transgenes; Transgenic Mice; Transgenic Organisms; Vaccines; Viral; Virus; Work; abstracting; antigen processing; cytokine; in vivo; insight; model development; neutralizing antibody; pathogen; programs; public health relevance; research study; respiratory virus; response; uptake

DESCRIPTION (provided by applicant): Summary/Abstract Production of high affinity antibody responses depend on productive interaction between antigen specific B cells and follicular helper CD4 T cells (Tfh) in secondary lymphoid tissue. The vast majority of studies performed thus far on the Tfh lineage of CD4 T cells have focused on the key regulatory and genetic events associated with their development. However, little is known about the repertoire selection of Tfh drawn from the polyclonal endogenous pool of CD4 T cells. A currently accepted model for the development of Tfh cells is that they are first primed by encounter with antigen-bearing dendritic cells (DC) and subsequently have their differentiation program solidified by cognate interaction with antigen-specific B cells. We hypothesize that because of the requisite requirement for cognate B cell interaction with CD4 T cells for full Tfh commitment, the peptide specificity of Tfh cells will reflect these differences in epitope display by antigen-specific B cels. We will test this hypothesis through use of two distinct genetic strategies perturb B cell presentation of antigen in vivo. First, we will selectively alter the composition of the antigen processing compartments of B cells through elimination of key endosomally localized thiolreductase within this subset of antigen presenting cells. Second, we will promote immunoglobulin mediated uptake of antigen through a dominant B cell receptor by use of an immunoglobulin transgenic mouse and a set of epitope tagged antigens. We have recently developed experimental strategies to isolate Tfh cells and to analyze the immunodominance hierarchy drawn from the endogenous CD4 repertoire using preparative flow cytometry and peptide-specific cytokine ELISpot assays. We will use these methods in conjunction with the genetic models of B cell presentation of antigen in vivo. In addition to providing direct evidence for the role of B cell epitope display in selecting the repertoire of Tfh cells, and thus clarifyin the final step in Tfh repertoire development, the results of our study will have several important implications for future work. First, they offer a roadmap for enhancing Tfh selection and thus antibody responses. They also provide a model to study the fate of Tfh that fail to be selected by B cells for Tfh repertoire. Finally, these studies may provide insight into CD4 T cell repertoire development when antigen- specific B cells are of limited specificity, as occurs in some autoimmune diseases and in the response to some viral pathogens and vaccines such as HIV, and respiratory viruses such as influenza. We will have developed the model systems and experimental approaches needed to dissect the molecular events in B cell antigen presentation that control follicular helper cell repertoire development.

描述（由申请人提供）：概述/摘要高亲和力抗体应答的产生取决于次级淋巴组织中抗原特异性B细胞和滤泡辅助性CD 4 T细胞（Tfh）之间的有效相互作用。迄今为止，对CD 4 T细胞的Tfh谱系进行的绝大多数研究都集中在与其发育相关的关键调控和遗传事件上。然而，很少有人知道从多克隆内源性库的CD 4 T细胞的Tfh的剧目选择。目前接受的Tfh细胞发育模型是，它们首先通过与携带抗原的树突细胞（DC）相遇而引发，随后通过与抗原特异性B细胞的同源相互作用而使其分化程序固化。我们假设，由于同源B细胞与CD 4 T细胞相互作用以实现完全Tfh定型的必要条件，Tfh细胞的肽特异性将反映抗原特异性B细胞表位展示的这些差异。我们将通过使用两种不同的遗传策略干扰B B细胞在体内呈递抗原来检验这一假设。首先，我们将通过消除抗原呈递细胞亚群内关键的内体定位的巯基还原酶来选择性地改变B细胞的抗原加工区室的组成。第二，我们将通过使用免疫球蛋白转基因小鼠和一组表位标记的抗原，促进免疫球蛋白介导的通过显性B细胞受体的抗原摄取。我们最近开发的实验策略，分离Tfh细胞和分析的免疫优势的层次结构，从内源性CD 4库使用制备流式细胞术和肽特异性细胞因子ELISpot测定。我们将结合B细胞在体内呈递抗原的遗传模型使用这些方法。除了为B细胞表位展示在选择Tfh细胞库中的作用提供直接证据，从而阐明Tfh库开发的最后一步外，我们的研究结果将对未来的工作有几个重要的意义。首先，它们提供了增强Tfh选择和抗体应答的路线图。它们还提供了一种模型来研究未能被B细胞选择用于Tfh库的Tfh的命运。最后，这些研究可提供对当抗原特异性B细胞具有有限特异性时的CD 4 T细胞库发育的了解，如在一些自身免疫性疾病中以及在对一些病毒病原体和疫苗（如HIV）和呼吸道病毒（如流感）的应答中发生的。我们将开发出所需的模型系统和实验方法来剖析控制滤泡辅助细胞谱系发育的B细胞抗原呈递中的分子事件。