Project 1 - Beryllium Antigen: HLA Peptide, Metal Interactions

由于已知抗原和可接近的靶器官，慢性铍病（CBD）是一种 重要器官特异性免疫介导疾病。CBD由铍暴露引起， 随着铍特异性、分泌Th型亮氨酸的CD 4 * T细胞在肺中的积累。先前 研究已经帮助确定了T细胞抗原受体（TCR）的遗传和功能重要性， HLA-DP 2在CBD免疫发病机制中的作用尽管我们对宇宙的理解 铍诱发疾病的免疫发病机制，铍如何与主要组织相容性结合 复合物11类（MHCII）分子，随后被铍特异性004* T细胞识别 仍然未知。最近，我们小组对HLA-DP 2的结晶研究揭示了一种潜在的铍 在P-链和肽骨架中的氨基酸位置处的谷氨酸残基的结合位点。数据 表明铍直接结合HLA-DP 2，需要特定的肽来完成 apTCR配体。项目1修订版的中心目标是表征铍抗原 负责CD 4 * T细胞活化。设计了一系列实验来鉴定HLA-DP 2 完成apTCR配体和激活铍特异性CD 4 * T细胞所需的肽表位。使用 建立方法和细胞模型系统后，具体实验将：1）定义 结合HLA-DP 2的肽，并确定这些肽的结合亲和力，2）描述 在铍盐存在下鉴定的HLA-DP 2结合肽允许通过 3）鉴定和表征由抗原特异性TCR中发现的T细胞亚群表达的TCR， 对识别的不同肽组有反应的CBD患者的支气管肺泡灌洗（BAL），和 4)确定HLA-DP 2/肽/铍复合物是否可用于识别和表征 CBD患者血液和BAL中的铍反应性CD 4 +T细胞，作为疾病的潜在生物标志物 和疾病进展。这项转化研究是多学科的，汇集了免疫学家， 生物化学家，HLA结构生物学家和物理学家，科学家，以确定的确切性质， CBD中的MHCII/BERGINE/肽/TCR关系。项目1与项目2通过提供功能 遗传流行病学发现的基础，并与项目3通过测试免疫生物标志物的结果 并行的措施。这一结果将提高对金属抗原结构/功能的理解， 产生数据以支持肽四聚体作为临床生物标志物的用途。

With a known antigen and an accessible target organ, chronic beryllium disease (CBD) serves as an important organ-specific, immune-mediated disease. CBD results from beryllium exposure and is associated with the accumulation of beryllium-specific, Thi-type cytokine-secreting CD4* T cells in the lung. Previous studies have helped identify the genetic and functional importance of the T cell antigen receptor (TCR) and HLA-DP2 in CBD immunopathogenesis. Despite the advances in our understanding of the immunopathogenesis of beryllium-induced disease, how beryllium binds to the major histocompatibility complex class 11 (MHCII) molecule and is subsequently recognized by beryllium-specific 004* T cells remains unknown. Recently, the crystallization of HLA-DP2 by our group has revealed a potential beryllium binding site to glutamic acid residues at amino acid positions in the p-chain and the peptide backbone. Data suggest that beryllium directly binds to HLA-DP2 and that particular peptides are required to complete the apTCR ligand. The central goal of this revision of Project 1 is to characterize the beryllium antigen responsible for CD4* T cell activation. A series of experiments has been designed to identify the HLA-DP2 peptide epitopes required to complete the apTCR ligand and activate beryllium-specific CD4* T cells. Using established methods and cell model systems, specific experiments will: 1) Define the sequence and motif of peptides that bind to HLA-DP2 and determine the binding affinities of those peptides, 2) Delineate which of the identified HLA-DP2 binding peptides in the presence of beryllium salt allow recognition of beryllium by antigen-specific TCRs, 3) Identify and characterize the TCRs expressed by the subset of T cells found in the bronchoalveolar lavage (BAL) of patients with CBD that respond to the different peptide sets identified, and 4) Determine whether HLA-DP2/peptide/beryllium complexes can be used to identify and characterize beryllium-reactive CD4+T cells in the blood and BAL of CBD patients, as a potential biomarker of disease and disease progression. This translational study is multidisciplinary, assembling immunologists, biochemists, HLA structural biologists, and physician-scientists to define the precise nature of the MHCII/Beryllium/Peptide/TCR relationship in CBD. Project 1 integrates with Project 2 by providing functional basis for genetic epidemiologic discoveries, and with Project 3 by testing immune biomarker outcome measures in parallel. The results will improve the understanding of metal antigen structure/function and result in data to support the use of peptide tetramers as clinical biomarkers.