Interactions between antigen-specific effector and regulatory T cells in beryllium-induced disease

 描述（由申请人提供）：慢性铍病（CBD）是一种肉芽肿性肺部疾病，由工作场所的铍暴露引起，其特征是铍特异性、分泌Th 1型亮氨酸的CD 4 + T细胞在肺中蓄积。遗传易感性与β链第69位含有谷氨酸的HLA-DP等位基因密切相关 （β Glu 69），并且大多数CD 4 + T细胞以HLA-DP限制性方式识别。我们已经开发了一种HLA-DP 2转基因（Tg）CBD小鼠模型，该模型复制了人类疾病中的许多发现。Be氧化物（BeO）暴露的HLA-DP 2 Tg小鼠在支气管血管周围分布中出现单核细胞浸润，主要由效应和调节性CD 4 + T细胞组成。BeO暴露的HLA-DP 2 Tg小鼠中存在Be反应性、HLA-DP 2限制性CD 4 + T细胞，但野生型小鼠中不存在。BeO暴露的HLA-DP 2 Tg小鼠中Treg细胞的消耗加剧肺部炎症并增强肉芽肿形成，表明Treg细胞抑制Be特异性效应CD 4 T细胞和肉芽肿性炎症。此外，我们最近已经鉴定了Be依赖性模拟表位和自身肽，包括来自丛蛋白A蛋白的那些肽，其刺激来自CBD患者肺部的Be特异性CD 4 + T细胞。使用负载Be的HLA-DP 2-丛蛋白A4四聚体，已经在所有表达HLA-DP 2的CBD患者和大多数BeO暴露的HLA-DP 2 Tg小鼠的支气管肺泡灌洗液（BAL）中鉴定了对该αβTCR配体特异性的CD 4 + T细胞。此外，CBD患者和BeO暴露小鼠肺中的HLA-DP 2-丛蛋白A4/Be四聚体染色的CD 4 + T细胞的子集表达FoxP 3，表明表位特异性Treg细胞的诱导。驱动BeO暴露的HLA-DP 2 Tg小鼠的肺中抗原特异性效应T细胞和Treg细胞的募集和/或扩增的因素、这些T细胞亚群之间的相互作用以及它们如何调节肉芽肿发展形成了当前提议的基础。因此，我们假设Be暴露诱导Be特异性效应CD 4 T细胞和Treg细胞之间的动态相互作用，并且这些不同的抗原特异性T细胞亚群的扩增调节对Be的免疫应答。使用逆转录TCR HLA-DP 2 Tg小鼠，第一个具体目的将确定Be特异性CD 4 + T细胞在Be诱导的肉芽肿性炎症产生中的致病性，而第二个目的将评估Treg细胞在Be特异性肉芽肿性免疫应答产生中的作用。在第三个具体目标中，我们将把我们的发现从HLA-DP 2 Tg小鼠转化为患有CBD的人类受试者。与任何其他人类肺部疾病不同，我们的提案的新奇源于我们以抗原特异性方式研究小鼠和人类肺部适应性免疫应答的发展并分析对相同抗原复合物特异性的效应细胞和Treg细胞之间的相互作用的能力。总之，这些研究将加强我们对CBD免疫发病机制的理解，并可能导致免疫抑制剂的治疗替代品。

 DESCRIPTION (provided by applicant): Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by be exposure in the workplace and is characterized by the accumulation of Be-specific, Th1-type cytokine-secreting CD4+ T cells in the lung. Genetic susceptibility is strongly linked to HLA-DP alleles that contain a glutamic acid at the 69th position of the β-chain (βGlu69), and the majority of CD4+ T cells recognize is in an HLA-DP-restricted manner. We have developed an HLA-DP2 transgenic (Tg) mouse model of CBD that replicates many of the findings seen in the human disease. Be oxide (BeO)-exposed HLA-DP2 Tg mice develop mononuclear infiltrates in a peribronchovascular distribution that are predominantly composed of effector and regulatory CD4+ T cells. Be-responsive, HLA-DP2- restricted CD4+ T cells are present in BeO-exposed HLA-DP2 Tg mice but not in wild-type mice. Depletion of Treg cells in BeO-exposed HLA-DP2 Tg mice exacerbates lung inflammation and enhances granuloma formation, suggesting that Treg cells inhibit Be-specific effector CD4 T cells and granulomatous inflammation. In addition, + we have recently identified Be-dependent mimotopes and self-peptides, including those derived from plexin A proteins, that stimulate Be-specific CD4+ T cells derived from the lungs of CBD patients. Using Be-loaded HLA- DP2-plexin A4 tetramers, CD4+ T cells specific for this αβTCR ligand have been identified in the bronchoalveolar lavage (BAL) fluid of all HLA-DP2-expressing CBD patients and the majority of BeO-exposed HLA-DP2 Tg mice. Furthermore, a subset of HLA-DP2-plexin A4/Be tetramer-staining CD4+ T cells in the lung of CBD patients and BeO-exposed mice express FoxP3, indicating the induction of epitope-specific Treg cells. The factors driving the recruitment and/or expansion of antigen-specific effector T cells and Treg cells in the lungs of BeO-exposed HLA- DP2 Tg mice, the interplay between these T cell subsets and how they modulate granuloma development form the basis of the current proposal. Thus, we hypothesize that Be exposure induces a dynamic interplay between Be-specific effector CD4 T cells and Treg cells and that the expansion of these distinct antigen-specific T cell subsets modulates the immune response to Be. Using retrogenic TCR HLA-DP2 Tg mice, the first specific aim will determine the pathogenicity of Be-specific CD4+ T cells in the generation of Be-induced granulomatous inflammation while the second aim will assess the role of Treg cells in the generation of a Be-specific granulomatous immune response. In the third specific aim, we will translate our findings from HLA-DP2 Tg mice to human subjects with CBD. Unlike any other human lung disease, the novelty of our proposal stems from our ability to study the development of an adaptive immune response in the lungs of mice and humans in an antigen- specific manner and analyze the interaction between effector and Treg cells specific for the same antigenic complex. Together, these studies will strengthen our understanding of immunopathogenesis of CBD and potentially lead to therapeutic alternatives to immunosuppressive agents.