Role of Nuclear Factor TOX in Germinal Center Reactions

描述(由申请人提供)：高亲和力保护性抗体反应的产生需要T和B细胞在称为生发中心的次级淋巴组织的专门区域进行合作。了解这些细胞相互作用的调节对于疫苗开发和理解生发中心淋巴细胞在肿瘤发展和自身免疫中的作用是重要的。T滤泡辅助细胞(TFH)是一种特殊的CD4T细胞，能够迁移到滤泡并向B细胞传递辅助信号，从而在体液免疫反应的功能成熟过程中发挥关键作用。基因表达的全局分析表明，生发中心B细胞和TFH都有独特的基因表达模式，这使它们有别于其他亚群的幼稚和活化的淋巴细胞。据报道，在生发中心B细胞和TFH中都有特异表达的基因之一编码TOX，这是一种在啮齿动物和人类之间高度保守的蛋白质，在我们的实验室中首次被发现是T细胞发育的调节因子。我们已经培育出了TOX转基因小鼠和TOX全球缺陷型小鼠，并证明了TOX对于CD4T细胞谱系的发展是必需的。使用这些转基因动物的组合，我们建议在这里确定TOX是否也在生发中心反应中发挥作用。我们的方法使我们能够区分TOX缺乏对B细胞和T细胞的影响。因此，将条件TOX缺陷小鼠培育成在B细胞系中表达Cre重组酶的小鼠，将被用于寻找免疫后生发中心B细胞形成和功能的缺陷。提出了两种互补的方法来类似地研究TOX在TFH发育和功能中的作用：用胸腺表达的TOX转基因来补充全球TOX缺陷小鼠，以及在体外Cre介导的CD4+T细胞中Tox基因的缺失，随后在体内测试TFH的发育和功能。为了补充这些研究，我们还建议产生一种TOX报告敲除小鼠品系，使我们能够跟踪TOX在活细胞中和免疫反应期间在体内的表达。 公共卫生相关性：保护性抗体介导的免疫反应需要T和B淋巴细胞在次级淋巴组织的特定区域相互作用，称为生发中心。了解这些相互作用的调节对于疫苗开发和理解生发中心淋巴细胞在肿瘤发展和自身免疫中的作用是重要的。这项研究计划旨在了解一种在啮齿动物和人类中高度保守的特定核蛋白在调节这些生发中心反应中的作用。

DESCRIPTION (provided by applicant): The generation of a high affinity protective antibody response requires T and B cell collaboration in specialized areas of secondary lymphoid tissue known as germinal centers. Understanding the regulation of these cellular interactions is important for vaccine development and for understanding the role of germinal center lymphocytes in tumor development and autoimmunity. T follicular helper cells (TFH) are specialized CD4 T cells that are able to migrate into follicles and deliver helper signals to B cells, and thus play a critical role in functional maturation of a humoral immune response. Global analysis of gene expression has shown that both germinal center B cells and TFH have unique patterns of gene expression that distinguish them from other subsets of naive and activated lymphocytes. One of the genes reported to be expressed specifically in both germinal center B cells and TFH encodes TOX, a protein highly conserved between rodents and humans and first identified in our laboratory as a regulator of T cell development. We have produced TOX transgenic mice and globally and conditionally TOX-deficient mice and have shown that TOX is required for development of the CD4 T cell lineage. Using combinations of these genetically modified animals, we propose here to determine whether TOX also plays a role in germinal center reactions. Our approaches allow us to distinguish the effects of TOX-deficiency on B and T cells. Thus, breeding conditionally TOX-deficient mice to mice that express Cre recombinase in the B cell lineage will be used to look for defects in germinal center B cell formation and function upon immunization. Two complementary approaches are proposed to study similarly the role of TOX in TFH development and function; complementation of globally TOX-deficient mice with a thymically expressed TOX transgene and in vitro Cre-mediated deletion of the Tox locus in CD4+ T cells that are subsequently tested for TFH development and function in vivo. To complement these studies we also propose to generate a TOX reporter knock-in strain of mice that will allow us to track expression of TOX in viable cells and in vivo during an immune response. PUBLIC HEALTH RELEVANCE: A protective antibody-mediated immune response requires T and B lymphocyte interactions in specialized areas of secondary lymphoid tissue known as germinal centers. Understanding the regulation of these interactions is important for vaccine development and for understanding the role of germinal center lymphocytes in tumor development and autoimmunity. This research program is directed at understanding the role of a specific nuclear protein, highly conserved in rodents and humans, in regulating these germinal center reactions.