B Cell Traffic in Type I Diabetes Mellitus

描述(由申请人提供)： I型糖尿病(T1 DM)是一种由自身免疫破坏产生胰岛素的胰岛β细胞引起的破坏性疾病。TIDM是由T细胞介导的；B细胞也是必不可少的。我们的长期目标是阐明B淋巴细胞迁移到并保留在自身免疫攻击部位的机制，并利用这些信息设计治疗方案来扰乱这些途径并改变病理过程。具体的假设是趋化因子将B细胞招募到胰岛，在那里它们贡献炎症信号，推动良性胰腺炎发展为压倒性疾病。我们的假设基于这样的观察：1)我们发现大的、组织良好的B细胞在胰岛中渗透，2)将B细胞从胰岛重新分布的实验技术是保护性的，3)B细胞受体特异性(BCR)深刻地影响疾病以及B细胞的胰岛定位。这项建议的具体目的是：1)识别吸引B淋巴细胞进入非肥胖糖尿病小鼠胰岛的分子信号，并利用这些信息阻止B细胞进入炎症部位。我们将通过跨孔迁移和过继转移研究来研究CXCL13对B细胞向胰岛迁移的影响。接下来将在体内阻断这些信号，以确定对自然B细胞定位和疾病的影响。2)确定B细胞特异性和活化状态对炎症胰岛进入和滞留的影响。我们已经设计了两个NOD小鼠品系，表达胰岛素(促进疾病)或非胰岛抗原(保护性)的BCR。我们将使用过继转移、跨井迁移和共聚焦成像来比较这些小鼠的幼稚B细胞、抗原激活B细胞和T细胞激活B细胞的胰岛趋化因子反应。3)建立B细胞趋化改变的TIDM小鼠模型，进一步阐明B细胞定位在TIDM中的作用。这些研究将确定B淋巴细胞进入自身免疫攻击部位的机制，并可能确定TIDM的新干预靶点。

DESCRIPTION (provided by applicant): Type I diabetes mellitus (T1DM) is a devastating disorder resulting from autoimmune destruction of insulin-producing pancreatic beta cells. TIDM is T cell mediated; B cells are also essential. Our long term goal is to elucidate the mechanisms by which B lymphocytes migrate to and are retained at sites of autoimmune attack and to use this information to design therapeutic options to disrupt those pathways and alter the pathological process. The specific hypothesis is that chemokines recruit B cells to pancreatic islets, where they contribute inflammatory signals driving benign insulitis to overwhelming disease. We base that hypothesis on the observations that: 1) we find large, well-organized B cell infiltrates in the islets, 2) an experimental technique which redistributes B cells away from islets is protective, 3) B cell receptor specificity (BCR) profoundly impacts disease as well as islet localization of B cells. The specific aims of this proposal are to: 1) identify the molecular signals that attract B lymphocytes to the islets of Non-Obese Diabetic mice and use this information to block B cell entry into the site of inflammation. We will investigate the effects of CXCL13 on B cell migration to the islets using transwell migration and adoptive transfer studies. In-vivo blockade of these signals to determine effects on native B cell localization and disease will follow. 2) Determine the effects of B cell specificity and activation status on entry into and retention in inflamed islets. We have engineered two NOD mouse lines expressing BCRs specific for insulin (disease-promoting), or a non-islet antigen (protective). We will compare the islet chemokine responses of naive, antigen-engaged, and T-cell-activated B cells from these mice using adoptive transfer, transwell migration, and confocal imaging. 3) Develop a mouse model of TIDM in which B cell chemoattraction is altered to further clarify the effects of B cell localization in this disease. These studies will identify the mechanims that mediate entry of B lymphocytes into a site of autoimmune attack and may identify novel targets of intervention in TIDM.