B cell functional and signaling abnormalities in SLE

描述（由申请人提供）：一般认为B淋巴细胞耐受过程中的缺陷是系统性红斑狼疮（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鼠模型中显而易见，其表明淋巴细胞信号传导中的特异性缺陷可导致SLE样表型。为了定义耐受机制并在人类中测试上述假设，他们开发了一种新的系统来跟踪自我反应性B细胞。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志物。 初步结果支持这一假设，即B淋巴细胞耐受性是有缺陷的SLE，特别是在幼稚记忆B细胞的过渡扰乱。在这一过渡期间，容忍在何处以及如何被废除，仍有待确定。 目前的建议将集中在进一步细化的分布自身反应性B细胞到不同的子集，通过流式细胞术和免疫组化沿着幼稚记忆的转变，在外周血和淋巴组织从狼疮患者，以确定具体的耐受性被废除。目的2将通过与正常对照相比，狼疮初始B细胞中信号传导和功能缺陷的特征，并将其与耐受性丧失相关联，来询问耐受性逃逸的机制是什么。将通过钙通量、酪氨酸磷酸化和下游信号传导途径的募集来测量信号转导。功能分析将包括增殖反应和活化标志物表达的测定。目标3将定义在用以系统方式靶向B细胞的特异性免疫疗法治疗后上述异常发生了什么。通过计数B细胞亚群和表征B细胞耗竭前后狼疮B细胞中信号转导和功能的缺陷，他们将进一步阐明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，作为一名学术风湿病学家，该项目和职业奖与罗切斯特大学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者的发展。

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.