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）： 摘要/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 CD4 T 细胞 (Tfh) 之间的有效相互作用。迄今为止，针对 CD4 T 细胞 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，人们对从 CD4 T 细胞多克隆内源库中提取的 Tfh 的库选择知之甚少。目前公认的 Tfh 细胞发育模型是，它们首先通过与携带抗原的树突状细胞 (DC) 相遇而启动，随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。我们假设，由于同源 B 细胞与 CD4 T 细胞相互作用以实现完全 Tfh 承诺，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扰乱体内抗原的 B 细胞呈递来检验这一假设。首先，我们将通过消除抗原呈递细胞子集中关键的内体定位硫醇还原酶来选择性地改变 B 细胞抗原加工区室的组成。其次，我们将使用免疫球蛋白转基因小鼠和一组表位标记的抗原，通过显性 B 细胞受体促进免疫球蛋白介导的抗原摄取。我们最近开发了实验策略来分离 Tfh 细胞，并使用制备型流式细胞术和肽特异性细胞因子 ELISpot 分析来分析从内源性 CD4 库中提取的免疫优势层次。我们将结合体内 B 细胞呈递抗原的遗传模型来使用这些方法。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 库开发的最后一步之外，我们的研究结果将对未来的工作产生几个重要的影响。首先，他们提供了增强 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 细胞选择为 Tfh 库的 Tfh 的命运。最后，这些研究可以深入了解当抗原特异性 B 细胞特异性有限时，CD4 T 细胞库的发育，如某些自身免疫性疾病以及对某些病毒病原体和疫苗（如 HIV）和呼吸道病毒（如流感）的反应。 。我们将开发出剖析控制滤泡辅助细胞库发育的 B 细胞抗原呈递分子事件所需的模型系统和实验方法。