Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045;
J Immunol. 2014 May 15;192(10):4571-80. doi: 10.4049/jimmunol.1400007. Epub 2014 Apr 9.
Chronic beryllium disease (CBD) is a granulomatous lung disease characterized by the accumulation of beryllium (Be)-specific CD4(+) T cells in bronchoalveolar lavage. These expanded CD4(+) T cells are composed of oligoclonal T cell subsets, suggesting their recruitment to the lung in response to conventional Ag. In the current study, we noted that all bronchoalveolar lavage-derived T cell lines from HLA-DP2-expressing CBD patients contained an expansion of Be-responsive Vβ5.1(+) CD4(+) T cells. Using Be-loaded HLA-DP2-peptide tetramers, the majority of tetramer-binding T cells also expressed Vβ5.1 with a highly conserved CDR3β motif. Interestingly, Be-specific, Vβ5.1-expressing CD4(+) T cells displayed differential HLA-DP2-peptide tetramer staining intensity, and sequence analysis of the distinct tetramer-binding subsets showed that the two populations differed by a single conserved amino acid in the CDR3β motif. TCR Vα-chain analysis of purified Vβ5.1(+) CD4(+) T cells based on differential tetramer-binding intensity showed differing TCR Vα-chain pairing requirements, with the high-affinity population having promiscuous Vα-chain pairing and the low-affinity subset requiring restricted Vα-chain usage. Importantly, disease severity, as measured by loss of lung function, was inversely correlated with the frequency of tetramer-binding CD4(+) T cells in the lung. Our findings suggest the presence of a dominant Be-specific, Vβ5.1-expressing public T cell repertoire in the lungs of HLA-DP2-expressing CBD patients using promiscuous Vα-chain pairing to recognize an identical HLA-DP2-peptide/Be complex. Importantly, the inverse relationship between expansion of CD4(+) T cells expressing these public TCRs and disease severity suggests a pathogenic role for these T cells in CBD.
慢性铍病（CBD）是一种肉芽肿性肺病，其特征是铍（Be）特异性 CD4+T 细胞在支气管肺泡灌洗液中的积累。这些扩增的 CD4+T 细胞由寡克隆 T 细胞亚群组成，表明它们响应常规抗原被募集到肺部。在本研究中，我们注意到，所有表达 HLA-DP2 的 CBD 患者的支气管肺泡灌洗衍生 T 细胞系均含有 Be 反应性 Vβ5.1+CD4+T 细胞的扩增。使用负载 Be 的 HLA-DP2-肽四聚体，大多数四聚体结合 T 细胞也表达 Vβ5.1，具有高度保守的 CDR3β 基序。有趣的是，Be 特异性、表达 Vβ5.1 的 CD4+T 细胞显示出不同的 HLA-DP2-肽四聚体染色强度，并且对不同四聚体结合亚群的序列分析表明，这两个群体在 CDR3β 基序中仅相差一个保守的氨基酸。基于不同四聚体结合强度对纯化的 Vβ5.1+CD4+T 细胞的 TCR Vα 链分析表明，存在不同的 TCR Vα 链配对要求，高亲和力群体具有混杂的 Vα 链配对，而低亲和力亚群需要限制的 Vα 链使用。重要的是，肺功能丧失衡量的疾病严重程度与肺部四聚体结合 CD4+T 细胞的频率呈负相关。我们的发现表明，在表达 HLA-DP2 的 CBD 患者的肺部存在一种主要的 Be 特异性、表达 Vβ5.1 的公共 T 细胞库，该库使用混杂的 Vα 链配对来识别相同的 HLA-DP2-肽/Be 复合物。重要的是，表达这些公共 TCR 的 CD4+T 细胞的扩增与疾病严重程度呈负相关，这表明这些 T 细胞在 CBD 中具有致病性作用。
