RECEPTOR DIVERSITY IN RECOGNITION OF INFLUENZA HA

描述：(改编自调查人员的摘要)目标 这项建议是为了分析影响耐受性和自身反应性的因素。 在转基因小鼠中表达该基因的小鼠辅助性T(Th)和B细胞 流感病毒A/PR/8/34血凝素(PR8 HA)是一种特性良好的 新自身抗原(HA-Tg小鼠)。HA特异性Th和B的能力 逃避来自原始T和B细胞的负选择的细胞 HATG小鼠分化和参与HA特异性的研究进展 将检查免疫反应。以下是以下具体问题 1)HA-TG小鼠体内HA特异性Th细胞的表型是什么？ HA TG小鼠将与表达T细胞受体的转基因小鼠交配 针对HA派生的II类受限的新自我的明确的特异性 多肽及其负选择的程度和基础 HA TG小鼠体内的HA特异性Th细胞将被测定。HA是否特定于 来自HA、TG和非TG(BALB/c)小鼠的TH细胞具有不同的能力 分化成不同的Th表型将被评估。方法： 表型(如Th1、Th2或自身反应性Thh)影响 HA特异性Th细胞为体液免疫或细胞免疫提供帮助 将对答复进行评估。2)血凝素B的表型是什么 HA-TG小鼠体内的细胞？HA特异性B细胞在多大程度上 在初次病毒免疫后被激活的人被否定地选择 在HA、TG小鼠的次级B细胞库形成过程中，将对其进行检测。 HA TG小鼠将被分析其次级B细胞的特异性 B细胞对含氨基酸替换突变病毒的应答 抗原位点，以确定阴性选择的PR8是否具有HA特异性 B细胞将HA TG小鼠的次级B细胞反应集中于突变型 (非自我)表位，并远离与新自我HA的反应。是否 血凝素特异性B细胞经历体细胞突变和/或负选择 HATG小鼠的生发中心通路将被评估。这个角色是 HA特异性B细胞在激活自身反应性Th细胞中将发挥作用 通过用分离的Th决定簇攻击HA TG小鼠与 完整的HA，HA特异的B细胞可以作为有效的抗原 呈现细胞。3)针对专业抗原进行靶向表达 提呈细胞影响HA如何被识别为新的自我抗原？ 透明质酸在直接参与免疫的细胞类型中的表达 谱系的形成影响自身反应性Th和B的负选择 将通过分析表达HA的TG小鼠来评估细胞 MHC II类启动子的控制。总而言之，这些研究将提供 对免疫谱系形成和免疫机制的基本见解 宽容。它们还将与以下进程直接相关 自身免疫，因为决定自身免疫功能潜能的因素 逃避负选择并被激活的自身反应性淋巴细胞 具有自身抗原结构相似性的病毒将被定义。

DESCRIPTION: (Adapted from the investigator's abstract) The objective of this proposal is to analyze factors governing tolerance and autoreactivity among murine helper T (Th) and B cells in transgenic mice that express the influenza virus A/PR/8/34 hemagglutinin (PR8 HA) as a well-characterized neo-self antigen (HA Tg mice). The capacities for HA-specific Th and B cells that evade negative selection from the primary T and B cell repertoires in HA Tg mice to differentiate and participate in HA-specific immune responses will be examined. The following specific questions will be addressed: 1) What is the phenotype of HA-specific Th cells in HA Tg mice? HA Tg mice will be mated to transgenic mice expressing T cell receptors with defined specificities toward HA-derived class II-restricted neo-self peptides, and the extent and basis of negative selection of these HA-specific Th cells in HA Tg mice will be determined. Whether HA-specific Th cells from HA Tg and non-Tg (BALB/c) mice have differing capacities to differentiate into distinct Th phenotypes will be assessed. How Th phenotype (e.g., Th1, Th2, or autoreactive Th) affects the ability of HA-specific Th cells to provide help for humoral or cell-mediated immune responses will be evaluated. 2) What is the phenotype of HA-specific B cells in HA Tg mice? The extent to which HA-specific B cells that are activated following primary virus immunization are negatively selected during secondary B cell repertoire formation in HA Tg mice will be examined. HA Tg mice will be analyzed for the specificity of their secondary B cell responses to mutant viruses containing amino acid substitutions in B cell antigenic sites, to determine whether negative selection of PR8 HA-specific B cells focuses the secondary B cell responses of HA Tg mice toward mutant (non-self) epitopes and away from reactivity with the neo-self HA. Whether HA-specific B cells undergo somatic mutation and/or negative selection in the germinal center pathway in HA Tg mice will be assessed. The role that HA-specific B cells play in the activation of autoreactive Th cells will be evaluated by challenging HA Tg mice with isolated Th determinants versus the intact HA, for which HA-specific B cells can act as potent antigen presenting cells. 3) Does targeting expression to professional antigen presenting cells influence how the HA is recognized as a neo-self antigen? How expression of the HA in cell types that participate directly in immune repertoire formation affects the negative selection of autoreactive Th and B cells will be evaluated by analyzing Tg mice that express the HA under the control of a MHC class II promoter. Together, these studies will provide fundamental insights into the mechanisms of immune repertoire formation and tolerance. They will also have direct relevance to the processes of autoimmunity, since factors that determine the functional potential of autoreactive lymphocytes that evade negative selection and are activated by viruses bearing structural similarities to self antigens will be defined.