Modeling FCRL6 regulation and function in transgenic mice

描述（由申请人提供）：鉴定一个由终末分化淋巴细胞表达的具有酪氨酸免疫调节特性的Fc受体样（FCRL）分子大家族开辟了一个新的研究领域。这些分子的基本免疫学重要性体现在它们的进化保守性，与现代适应性免疫的诞生同时出现，并与淋巴增生性、感染性、免疫缺陷和自身免疫性疾病有关。不幸的是，人类和小鼠之间明显的物种间多样性以及它们的配体的神秘性质限制了我们对它们的生物学作用的理解。FCRL6是本研究的重点，在成熟的人类细胞毒性NK和T淋巴细胞上具有区别性表达模式，在慢性疾病状态下在这些细胞上上调，可以招募SHP-2，最近发现与MHC II类相互作用。这种关系的发现揭示了细胞介导免疫调节的一个意想不到的途径。我们的中心假设是，人类FCRL6 BAC转基因（Tg）小鼠的发展将为定义FCRL6通过与MHC II类相互作用调节细胞毒性淋巴细胞效应功能的潜力提供关键的翻译工具。该研究具有创新性，因为它将开发Tg模型来克服人类和小鼠中该受体/基因的物种间多样性障碍，并建立体内系统来探索FCRL6/MHCII界面的生物学特性。我们的初步研究强烈表明，这种方法将为确定该分子的生物学功能提供重大突破。我们计划通过追求以下具体目标来验证中心假设：Aim 1提出表征并进一步发展最近产生的人类FCRL6 BAC Tg小鼠，Aim 2将使用这些小鼠研究FCRL6调节效应淋巴细胞对LCMV感染的反应及其HLA II类配体的影响。这项研究的贡献将是重要的，因为它将提供一个独特的机会，以克服我们理解的主要障碍。这一重大进展将产生一个广泛适用的系统，用于定义FCRL6/MHCII相互作用对细胞毒性效应淋巴细胞和免疫功能的生理影响。重要的是，为开展这些研究而集合的特殊资源和专业知识，很好地定位于充分利用该模型在未来免疫学研究中的潜力。这项工作的结果预计将产生积极的影响，因为由此产生的Tg小鼠将为FCRL6/MHCII关系在细胞免疫中的作用提供基本的见解。这个新的平台将是强大的和高度灵活的，用于扩大FCRL6/MHCII轴在广泛的免疫相关疾病、传染病和恶性肿瘤中的研究。这些研究还将促进开发新的靶向治疗干预措施，以调节与许多人类疾病相关的这种相互作用和效应淋巴细胞功能。

DESCRIPTION (provided by applicant): The identification of a large family of Fc receptor-like (FCRL) molecules expressed by terminally differentiated lymphocytes that possess tyrosine-based immunoregulatory properties has opened a new field of investigation. The fundamental immunologic importance of these molecules is indicated by their evolutionary conservation, emergence coincident with the birth of modern adaptive immunity, and associations with lymphoproliferative, infectious, immunodeficiency, and autoimmune disorders. Unfortunately, the interspecies diversity evident between human and mouse counterparts as well as the enigmatic nature of their ligands has limited our understanding of their biological roles. FCRL6, the focus of this proposal, has a discriminating expression pattern on mature human cytotoxic NK and T lymphocytes, is upregulated on these cells in chronic disease states, can recruit SHP-2, and has recently been found to interact with MHC class II. The discovery of this relationship exposes an unanticipated pathway in the regulation of cell-mediated immunity. Our central hypothesis is that the development of human FCRL6 BAC transgenic (Tg) mice will provide a critical translational tool for defining the potential of FCRL6 to regulate the effector function of cytotoxic lymphocytes through its interaction with MHC class II. The proposed research is innovative because it will develop a Tg model to overcome the hurdle of interspecies diversity evident for this receptor/gene in humans and mice and establish an in vivo system to explore the biology of the FCRL6/MHCII interface. Our preliminary studies strongly indicate that this approach will provide a significant breakthrough for determining the biological function of this molecule. We plan to test the central hypothesis by pursuing the following Specific Aims: Aim 1 proposes to characterize and further develop recently generated human FCRL6 BAC Tg mice and Aim 2 will use these mice to investigate FCRL6 regulation of effector lymphocyte responses to LCMV infection and the influence of its HLA class II ligand. The contribution of this research will be significant because it will provide a unique opportunity to surmount a major barrier in our understanding. This major advance will yield a widely adaptable system for defining the physiologic impact of the FCRL6/MHCII interaction on cytotoxic effector lymphocytes and immune function in general. Importantly, the exceptional set of resources and expertise assembled for conducting these studies is well positioned to take full advantage of the potential of this model in future immunologic investigation. The outcomes of this work are expected to have a positive impact because the resulting Tg mice will provide fundamental insight into the role of the FCRL6/MHCII relationship in cellular immunity. This new platform will be robust and highly flexible for expanding investigation of the FCRL6/MHCII axis in a broad number of immune-related disorders, infectious diseases, and malignancies. These studies will also facilitate the development of new targeted therapeutic interventions for modulating this interaction and effector lymphocyte function that are relevant to many human diseases. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public health because it will develop a novel system in mice to model the biological role of a human receptor and its interacting counterpart that regulate immune system cells critical for defense responses against viruses and malignant cells. The work will be important to NIH's mission because it will have broad impact that advances fundamental understanding of the immune system and has important implications for the development of new therapeutic approaches to patients with immune-related disorders.