Selection & Regulation of B Lymphocytes in IDDM

主要研究者/项目负责人（最后，第一，中间）：托马斯_詹姆斯W。说明.说明申请的广泛、长期目标和具体目标，并提及项目的健康相关性。简要描述研究设计和实现这些目标的方法。避免总结过去的成就和使用第一人称。本说明书旨在作为与申请分开时所提出的工作的简洁和准确的描述。如果该申请获得资助，本说明书将作为本项目的目标是了解1A型或胰岛素依赖型糖尿病（IDDM）中自身反应性B淋巴细胞的选择和调节。从长远来看，这些信息将用于确定诊断和治疗疾病的新靶点。临床和实验数据表明，胰岛素依赖型糖尿病是由于自身耐受性丧失和随后产生胰岛素的β细胞的自身免疫性破坏所致。虽然胰岛素、GAD和其他胰岛抗原的自身抗体被认为是免疫耐受丧失的早期指标，但大多数研究都集中在T淋巴细胞在疾病中的作用。最近的几项研究表明，B淋巴细胞在IDDM中也起关键作用。NOD小鼠是一种高度相关的IDDM动物模型，当B淋巴细胞被阻断或消除时，NOD小鼠可免受疾病过程的影响。此外，数据表明B淋巴细胞独特地能够呈递一些关键的β细胞抗原，并且它们的抗原呈递功能包括支配T细胞分化的能力。为了更好地理解B淋巴细胞在IDDM中的作用，产生了表达来自抗胰岛素mab 125的免疫球蛋白转基因（Tg）的NOD小鼠。虽然携带抗胰岛素转基因的B淋巴细胞在正常B6小鼠中功能性沉默，但相同的转基因在NOD中表达时表现出耐受性破坏。此外，当NOD小鼠被改造为仅携带来自mab 125的重链（HC）Tg（VH 125 Tg）时，这些动物以比非Tg对照显著更快的速率发展糖尿病。相比之下，NOD小鼠表达在其他方面相同的转基因（VH 281），不同之处仅在于胰岛素结合所需的两个氨基酸被保护免于发展糖尿病。当检查这些HC-Tg NOD的胰岛素结合B细胞的表达时，观察到来自VH 125 Tg NOD的B细胞受体（BCR）与内源性轻链联合收割机以产生胰岛素结合B细胞的异源群体，其中一些以高亲和力结合胰岛素。追踪VH 125 Tg NOD中的抗胰岛素B细胞显示BCR对胰岛素亲合力的变化与糖尿病发展的进展一致。这些观察结果表明，在胰岛素依赖型糖尿病的背景下，HC-Tg小鼠提供了一种独特的手段来跟踪抗胰岛素B细胞的命运和功能，这些细胞通常隐藏在一个大的多克隆库中。将B细胞作用与IDDM联系起来的细胞和分子机制将在以下具体目标中进行研究：I.表征NOD小鼠中伴随进行性β细胞破坏的胰岛素B细胞库的结构和功能变化。二.目的：了解2型糖尿病（T1 DM）发病过程中侵袭胰岛的B淋巴细胞的多样性及其功能。三.确定在T1 DM背景下，启动T细胞对胰岛素和胰岛素原的应答对B淋巴细胞的需求。四.表征受体识别β细胞自身抗原的B细胞的抗原呈递功能。成为公共信息。因此，不包括专有/机密信息。不要超过绩效现场=

Principal Investigator/Program Director (Last, first, middle): Thomas_ James W. DESCRIPTION. State the application's broad, long-term objectives and specific aims, making reference to the health relatedness of the project. Describe concisely the research design and methods for achieving these goals. Avoid summaries of past accomplishments and the use of the first person. This description is meant to serve as a succinct and accurate description of the proposed work when separated from the application. If the application is funded, this description, as is, will The goal of this project is to understand the selection and regulation of autoreactive B lymphocytes in Type 1A or insulin dependent diabetes mellitus (IDDM). In the long term this information will be used to identify new targets for the diagnosis and treatment of the disorder. Clinical and experimental data indicate that IDDM results from loss of self-tolerance and subsequent autoimmune destruction of insulin producing beta cells. Although autoantibodies to insulin, GAD and other islet antigens are recognized as early indicators of loss of immunological tolerance, most studies focus on the role of T lymphocytes in the disease. Several recent studies indicate that B lymphocytes also play a critical role in IDDM. NOD mice, a highly relevant animal model of IDDM, are protected from the disease process when B lymphocytes are blocked or eliminated. Further, data indicate that B lymphocytes are uniquely able to present some key beta cell antigens, and their antigen presenting function includes the ability to govern T cell differentiation. To better understand the role of B lymphocytes in IDDM, NOD mice were produced that express immunoglobulin transgenes (Tg) from anti-insulin mab125. While B lymphocytes that carry anti-insulin transgenes are functionally silenced in normal B6 mice, the same transgenes demonstrate breaches of tolerance when expressed in NOD. In addition, when NOD mice are engineered to harbor only the heavy chain (HC) Tg from mab125 (VH 125Tg), these animals develop diabetes at a significantly faster rate than non-Tg controls. In contrast, NOD mice expressing an otherwise identical transgene (VH281) that differs in only two amino acids that are required for insulin binding are protected from developing diabetes. When these HC-Tg NOD were examined for expression of insulin binding B cells, B cell receptors (BCR) from VH 125Tg NOD were observed to combine with endogenous light chains to produce a heterogenous population of insulin binding B cells some of which bind insulin with high affinity. Tracking anti-insulin B cells in VH125Tg NOD shows that changes in BCR avidity for insulin occurs in concert with progression to diabetes development. These observations indicate that in the context of IDDM, HC-Tg mice provide a unique means to track the fate and function of anti-insulin B cells that are usually buried in a large polyclonal repertoire. The cellular and molecular mechanisms that connect B cell actions to IDDM will be examined in the following specific aims: I. To characterize the shifts in structure and function of a B cell repertoire for insulin that accompanies progressive beta cell destruction in NOD mice. II. To understand the diversity and function of B lymphocytes that invade pancreatic islets in the course of T1DM. III. To determine the requirement for B lymphocytes in the initiation of T cell responses to insulin and proinsulin in the context of T1DM. IV. To characterize the antigen presenting function of B cells whose receptors recognize a beta cell autoantigen. become public information. Therefore, do not include proprietary/confidential information. DO NOT EXCEED PERFORMANCE SITE ========================================Section End===========================================