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

我们之前报道了系统性自身免疫性疾病中的寡克隆T细胞积累。例如，在系统性红斑狼疮（SLE）患者的外周血和受累肾脏以及类风湿关节炎（RA）患者的滑膜组织中检测到T细胞克隆扩增。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，我们尝试利用含有MHC分子的随机肽噬菌体文库和从临床样本中重建的TCR建立抗原肽筛选系统。结果表明，HLAB5101和H-2Db与β微球蛋白在噬菌体上表达，具有结合抗原肽的能力。进一步，我们从SLE患者临床样本的1个T细胞中获得TCR a链和b链成对，采用单细胞PCR方法在体外重建TCR为单链。重建的TCR与随机肽库的结合将成为确定克隆扩增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.