The role of follicular helper T cell cytokines in the IgE response

描述(申请人提供)：哮喘是一种慢性炎症性疾病，经常与过敏成分有关。哮喘是一个主要的公共卫生负担。在过去的40年里，这种疾病的流行率大大增加，但关于导致这种疾病的基本机制的许多问题仍然没有得到回答。高亲和力、变应原特异性的IgE抗体与过敏性哮喘的发病机制密切相关，参与IgE产生的途径如通过白细胞介素4(IL-4)传递信号一样。一个独特的CD4T细胞亚群被称为滤泡辅助T细胞(TFH细胞)，存在于生发中心(GC)，在那里它们在产生高亲和力抗体以及通过产生IL-4向IgE的同型转换中提供关键帮助。TFH细胞还分泌IL-21，这是一种抑制转换为IgE的细胞因子，表明TFH细胞、细胞因子的产生和同型转换之间存在复杂的关系。这一建议试图验证这样的假设，即TFH细胞独立地调节IL-4和IL-21的产生，以协调GC反应并激发IgE的产生。本文提出了三个具体目标来验证这一假说。第一个目的是通过细胞内染色确定TFH细胞亚群，并利用表达荧光报告基因的突变小鼠，研究TFH细胞与体内体液反应的关系。这些人群的组成将根据抗体滴度和GC反应在几种感染和免疫模型中以及跨时间和解剖位置进行测量。第二个目标是将分泌细胞因子的不同亚群的Tfh细胞与 他们正在与GC B细胞相互作用，并利用一种采用转移系统来测试这些个体群体的功能。在第三个目标中，将使用下一代测序和计算生物学中的先进技术来确定控制细胞因子产生的调控网络。总之，这项工作将进一步阐明TFH细胞控制过敏诱导的IgE抗体的机制，并在这样做的过程中确定破坏这一过程的靶点。此外，这份申请详细说明了申请者的培训计划，包括研究指导、高级课程工作、新技术培训以及科学专业精神、写作和数据展示方面的技能发展。哮喘等重大疾病的新疗法的开发依赖于这样的项目，这些项目将临床问题转化为基础研究问题。申请书中概述的研究和培训将使申请者为从事临床相关研究做好准备，成为一名独立的内科科学家。

DESCRIPTION (provided by applicant): Asthma is a chronic inflammatory disease and is frequently associated with an allergic component. Asthma poses a major public health burden. Prevalence of this disease has increased greatly over the last four decades yet many questions regarding the basic mechanisms that lead to this disease remain unanswered. High-affinity, allergen-specific IgE antibodies are strongly implicated in the pathogenesis of allergic asthma, as are pathways involved in IgE production such as signaling by interleukin-4 (IL-4). A unique subset of CD4 T cells termed follicular helper T cells (Tfh cells) are present in the germinal center (GC) where they provide critical help in the production of high-affinity antibodies as well as isotype class switching, including to IgE, via production of IL-4. Tfh cells also secrete IL-21,a cytokine that represses switching to IgE, suggesting a complex relationship between Tfh cells, cytokine production, and isotype switching. This proposal seeks to test the hypothesis that Tfh cells regulate the production of IL-4 and IL-21 independently to coordinate the GC response and evoke IgE production. Three specific aims are proposed to interrogate this hypothesis. The first aim will investigate the relationship between Tfh cells and the humoral response in vivo by defining subpopulations of Tfh cells by their cytokine secretion on the basis of intracellular staining as well as using mutant mice expressing fluorescent reporter genes. The composition of these populations will be measured in relation to antibody titer and the GC response in several models of infection and immunization and across time and anatomical location. The second aim is to directly connect different subpopulations of cytokine-secreting Tfh cells with the GC B cells they are interacting with, and to utilize an adoptive transfer system to test the function of these individual populations. In the third aim, regulatory networks controlling cytokin production will be determined using advanced techniques in next-generation sequencing and computational biology. Altogether, this work will further clarify the mechanism by which Tfh cells control allergy- inducing IgE antibodies and in doing so will identify targets for disrupting this process. In addition, this application details the applicant's training plan including research mentorship, advanced coursework, training in new techniques, and development of skills in scientific professionalism, writing, and presentation of data. The development of new treatments for major diseases like asthma depends on projects like this one which translate clinical problems into basic research questions. The research and training outlined in this application will prepare the applicant to pursue a career in the conduct of clinically relevant research as an independent physician scientist.