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: 8502860
• 负责人: Andrea Janine Sant
• 金额: $ 19.19万
• 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 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8502860
• 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)：高亲和力抗体反应的产生依赖于次级淋巴组织中抗原特异性B细胞和滤泡辅助CD4T细胞(TFH)之间的有效相互作用。到目前为止，对CD4T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节和遗传事件上。然而，关于从CD4T细胞的多克隆内源性池中选择TFH的谱系，人们知之甚少。目前公认的一种TFH细胞的发育模式是，首先与携带抗原的树突状细胞(DC)相遇，然后通过与抗原特异性B细胞的同源相互作用来固化其分化程序。我们推测，由于同源B细胞与CD4T细胞相互作用才能完全承担TFH，TFH细胞的多肽特异性将反映抗原特异性B细胞在表位显示上的这些差异。我们将通过使用两种不同的基因策略来检验这一假设，这两种策略扰乱了体内B细胞的抗原呈递。首先，我们将有选择地改变B细胞的抗原处理室的组成，通过消除这一抗原提呈细胞亚群中关键的内体定位的硫醇还原酶。其次，我们将利用免疫球蛋白转基因小鼠和一组表位标记抗原，通过优势B细胞受体促进免疫球蛋白介导的抗原摄取。我们最近开发了分离TFH细胞的实验策略，并使用制备流式细胞术和多肽特异性细胞因子ELISpot分析从内源性CD4谱系中提取的免疫优势等级。我们将把这些方法与体内B细胞呈递抗原的遗传模型结合使用。除了为B细胞表位显示在选择TFH细胞谱系中的作用提供直接证据，从而澄清TFH谱系发展的最后一步，我们的研究结果将对未来的工作有几个重要的启示。首先，它们提供了加强Tfh选择和抗体反应的路线图。他们还提供了一个模型来研究未能被B细胞选择用于TFH谱系的TFH的命运。最后，当抗原特异性B细胞具有有限的特异性时，这些研究可能提供对CD4T细胞谱系发育的洞察，例如在一些自身免疫性疾病中发生，在对一些病毒病原体和疫苗(如艾滋病毒)和呼吸道病毒(如流感)的反应中发生。我们将开发所需的模型系统和实验方法来剖析控制滤泡辅助细胞系发育的B细胞抗原呈递过程中的分子事件。