Pathogenic T Cells in Chronic Beryllium Disease

描述(申请人提供)：慢性铍病(CBD)的特征是肺部的肉芽肿性炎症和进行性纤维化。这种疾病是由工作场所接触铍引起的，它仍然是一个主要的公共卫生问题，估计有80万接触者目前处于危险之中。相当多的证据表明，CD4T细胞在CBD的发病机制中处于中心地位，该病与靶器官中铍特异的CD4T细胞的聚集有关。本应用研究的主要目的是阐明致病的CD4T细胞识别CBD中铍的机制。此前对慢性阻塞性肺疾病患者肺中CD4T细胞的研究表明，铍特异的T细胞大量寡克隆扩增，产生Th1型细胞因子。单个患者和不同患者之间的铍特异性T细胞致病亚群表达相同的相关T细胞受体(TCR)。其他研究已经证明，铍对致病的CD4T细胞的呈递取决于特定的人类白细胞抗原-DP等位基因，而存在铍的DP等位基因与疾病易感性有关。铍引起异常强烈的T细胞反应的基础及其与这些发现的关系尚不清楚。目前应用中的研究将检验这一假设，即CBD对Be的戏剧性反应与TCR与多组广泛表达的呈递人类白细胞抗原-DP-肽复合体的Be相互作用有关。对第一个特定目标的研究将确定与人类白细胞抗原-DP2结合的多肽的序列和基序，并允许抗原特异性TCRs识别铍。这些多肽序列和基序将用于鉴定和验证流行的自体多肽和蛋白质，这些多肽和蛋白质可能介导对铍的识别。在单独的研究中，将根据TCR的表达来表征对不同多肽组有反应的肺T细胞，以了解每个DP2-多肽/铍复合体是否诱导不同的或广泛重叠的反应T细胞亚群。其他研究将确定荧光DP2肽/铍多聚体(“四聚体”)是否可用于鉴定和表征慢性阻塞性肺疾病患者肺和外周血中的铍反应T细胞。最终目标的研究将确定为什么只有特定的HLA-DP等位基因似乎能够呈现铍，以及呈现是否仅限于DP。总之，这些研究将为CBD的免疫发病机制提供新的见解，并为其他CD4T细胞介导的疾病提供重要信息。

DESCRIPTION (provided by applicant): Chronic beryllium disease (CBD) is characterized by granulomatous inflammation and progressive fibrosis in the lung. The disease is caused by exposure to beryllium in the workplace, and it continues to be a major public health concern with an estimated 800,000 exposed individuals currently at risk. Considerable evidence indicates that CD4+ T cells are central to the pathogenesis of CBD and that disease is associated with the accumulation of beryllium-specific CD4+ T cells in the target organ. The major goal of the studies in this application is to elucidate the mechanism by which pathogenic CD4+ T cells recognize beryllium in CBD. Previous studies of CD4+ T cells in the lungs of CBD patients have shown large oligoclonal expansions of beryllium-specific T cells that produce Th1-type cytokines. Pathogenic subsets of beryllium-specific T cells in individual patients and among different patients were noted to express the same related T cell receptors (TCRs). Other studies have demonstrated that presentation of beryllium to pathogenic CD4+ T cells is dependent on particular alleles of HLA-DP, and the DP alleles that present beryllium match those implicated in disease susceptibility. The basis for the unusually strong T cell response elicited by beryllium and how it relates to these findings is unclear. Studies in the current application will test the hypothesis that the dramatic response to beryllium in CBD relates to TCR interactions with multiple widely expressed sets of beryllium presenting HLA-DP-peptide complexes. Studies in the first specific aim will define the sequence and motif of peptides that bind to HLA-DP2 and that allow recognition of beryllium by antigen-specific TCRs. The peptide sequences and motifs will be used to identify and verify prevalent self-peptides and proteins that are likely to mediate recognition of beryllium. In separate studies, lung T cells that respond to the different peptide sets will be characterized in regard to TCR expression to understand whether each DP2- peptide/beryllium complex induces distinct or broadly overlapping subsets of responding T cells. Additional studies will determine whether fluorescent DP2-peptide/beryllium multimers ("tetramers") can be used to identify and characterize beryllium-reactive T cells in the lungs and peripheral blood of patients with CBD. Studies in the final aim will determine why only certain HLA-DP alleles seem to be capable of presenting beryllium and whether presentation is limited to DP. Together, these studies will provide new insight into the immunopathogenesis of CBD as well as important information for other CD4 + T cell mediated diseases.