B cell functional and signaling abnormalities in SLE

描述(由申请人提供)：B淋巴细胞耐受过程中的缺陷被认为是系统性红斑狼疮(SLE)发病机制的核心。此外，B细胞受体(BCR)信号强度对于调节耐受性的重要性从自身免疫的小鼠模型中可见一斑，该模型表明淋巴细胞信号的特定缺陷可导致SLE样表型。为了确定人类的耐受机制并验证上述假说，他们开发了一种追踪自身反应性B细胞的新系统。该系统利用特异性抗体可变区基因片段VH4.34作为自身反应性的替代标记。初步结果支持这样的假设，即SLE患者对B淋巴细胞的耐受性存在缺陷，尤其是在幼稚的B细胞向记忆性B细胞的转变过程中受到干扰。在这一过渡期间，容忍在哪里以及如何被废除仍有待定义。 目前的建议将集中于通过流式细胞术和免疫组织化学进一步细化自身反应性B细胞在狼疮患者外周血和淋巴组织中从幼稚到记忆的转变过程中的不同亚群分布，以便具体确定耐受被取消的位置。目标2将通过描述狼疮幼稚B细胞与正常对照相比在信号和功能上的缺陷，并将其与耐受性丧失联系起来，询问耐受性逃避的机制是什么。信号转导将通过钙流、酪氨酸磷酸化和下游信号通路的重新启动来衡量。功能分析将包括确定增殖反应和激活标志物的表达。目标3将定义在系统地以B细胞为靶点的特定免疫疗法治疗后，上述异常会发生什么。通过对B细胞亚群的计数和对B细胞耗尽前后狼疮B细胞信号转导和功能缺陷的描述，将进一步阐明B细胞在SLE免疫发病机制中的关键作用。 鉴于了解免疫耐受性丧失的基本机制的长期目标，作为一名学术风湿学家，这个项目和职业奖项与罗切斯特大学提供的互动研究环境和指导相结合，旨在促进候选人作为基础科学免疫学家和独立研究员的发展。

DESCRIPTION (provided by applicant): It is thought that defects in the process of B lymphocyte tolerance are central to the pathogenesis of systemic lupus erythernatosus (SLE). Moreover, the importance of B cell receptor (BCR) signal strength for the regulation of tolerance is evident from murine models of autoimmunity which suggest that specific defects in lymphocyte signaling can lead to SLE-like phenotypes. In order to define tolerance mechanisms and test the above hypotheses in humans, they have developed a novel system to track self-reactive B cells. This system utilizes a specific antibody variable region gene segment, VH4.34, as a surrogate marker of autoreactivity. Preliminary results support the hypothesis that B lymphocyte tolerance is defective in SLE and is in particular perturbed during the naive to memory B cell transition. Exactly where and how tolerance is abrogated during this transition remains to be defined. The present proposal will focus on further refining the distribution of autoreactive B cells into distinct subsets by flow cytometry and immunohistochemistry along the naive to memory transition in peripheral blood and lymphoid tissue from lupus patients in order to determine specifically where tolerance is abrogated. Aim 2 will ask what the mechanism of tolerance escape is by characterizing defects in signaling and function in lupus naive B cells compared to normal controls and correlating this with loss of tolerance. Signal transduction will be measured by calcium fluxes, tyrosine phosphorylation, and recruitment of downstream signaling pathways. Functional analysis will include determination of proliferative responses and expression of activation markers. Aim 3 will define what happens to the above abnormalities after treatment with a specific immunotherapy that targets B cells in a systematic fashion. By enumerating B cell subsets and characterizing defects in signal transduction and function in lupus B cells before and after B cell depletion, they will further elucidate the critical role of B cells in the immunopathogenesis of SLE. Given the long-term goal of understanding the basic mechanisms underlying the loss of immune tolerance, as an academic rheumatologist, this project and career award combined with the interactive research environment and the mentoring available at the University of Rochester is intended to foster the candidate's development as a basic science immunologist and independent investigator.