A method to determine antigen peptides for the conally expanded T cells in systemic autoimmune diseases

我们以前报道过在系统性自身免疫性疾病中寡克隆性T细胞聚集。例如，在系统性红斑狼疮(SLE)患者的外周血、受累肾脏和类风湿关节炎(RA)患者的滑膜组织中均检测到T细胞克隆性增殖。然而，这些积累或扩增的T细胞的靶分子仍有待确定，尽管它们对于了解疾病的发病机制非常重要。为了确定T细胞克隆型的抗原肽，我们利用MHC分子建立了抗原肽的随机噬菌体文库筛选系统，并从临床标本中重建了TCR。结果表明，HLAB5101和H-2DB与β-微球蛋白结合后能在噬菌体表面表达，并具有结合抗原肽的能力。此外，我们还从SLE患者的一个临床T细胞中用单细胞聚合酶链式反应获得了TCRa和TCRb链，并在体外将TCRa和b链重组为单链。将构建的TCR与随机多肽文库相结合，将是确定克隆扩增T细胞抗原的有力工具。

We previously reported oligoclonal T cell accumulation in the systemic autoimmune diseases. For instance, the T cell clonal expansion was detected in peripheral blood and also in affected kidney in systemic lupus erythematosus (SLE) and in synovial tissue in rheumatoid arthritis (RA). However, target molecules of these accumulated or expanded T cells remains to be determined, even though they are of great importance for understanding the pathogenesis of the diseases. To determine the antigen-peptides of the T cell clonotypes, we tried to establish screening system of antigenic peptides using random peptide phage library with MHC molecules and reconstructed TCR from clinical samples. As a result, we demonstrated that HLAB5101 and H-2Db with betamicroglobulin is expressed on phage with ability to bind antigenic peptides. Further, we obtained TCR a and b chain in pair from one T cell of clinical samples from patients with SLE, using single cell PCR and reconstructed the TCR as a single chain in vitro. Combination of the reconstructed TCR and randomized peptide library would be a powerful tool to determine the antigens for the clonally expanded T cells.