抗原特异TCR α和β链基因克隆及分子空间结构预测

Cloning of antigen-specific TCR α and β genes and their 3-D structure prediction

目的扩增弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)相关抗原特异T细胞克隆的全长TCRα和β链基因序列,并对其三维空间结构进行预测。方法从已鉴定的2例伴有克隆性增殖TCR Vα6和Vβ13亚家族T细胞的DLBCL患者外周血中克隆全长TCRα和β基因序列,利用Primer Premier 5.0分析软件推算其相应的氨基酸序列,并通过自动化蛋白质模建服务器SWISS-MODEL进行三维空间结构预测。然后利用蛋白质三维图像分析软件Rasmol对所获得的TCR三维空间结构进行显示和分析。结果获得DLBCL相关抗原特异TCRα6和β13全长基因序列及其氨基酸序列。2例患者的TCR Vα6的空间结构与PDB ID:3ffcD模型相似,序列同源性分别为92.16%和91.71%;而2个TCR Vβ13也均具有同一个空间结构模型PDB ID:2ialD,序列同源性分别为92.95%和92.18%。结论来自不同DLBCL患者外周血中克隆性增殖的TCR Vα6或Vβ13亚家族T细胞的TCR具有高度同源性的空间结构,提示其可能识别相同的肿瘤抗原表位。

Objective To amplify the full-length sequences of diffuse large B cell lymphoma（DLBCL）-associated antigen-specific TCR α and β genes and to predict three-dimensional（3-D） structure of the proteins.Methods The full-length TCR genes were amplified from the peripheral blood mononuclear cells（PBMCs） derived from 2 pathologically identified DLBCL patients for the TCR Vα6 and Vβ13 subfamily T-cell clones,and their amino acid sequences were deduced by primer premier 5.0 analytical software.3-D spatial structures of the TCR α and β were modeled by SWISS-MODEL,then displayed and analyzed by the analytical software of Rasmol.Results The full-length TCR genes and their amino acid sequences were obtained successfully.the TCR Vα6 chains from the 2 cases of DLBCL patients were of high homology not only in sequence（92.16% and 91.71%,respectively）,but also in the 3-D spatial structures,which displayed the same model（PDB ID：3ffcD） by the SWISS-MODEL homology-modeling server.While the TCR Vβ13 chains also used an identical model（PDB ID：3dx9D）,and sequence homology was 92.95% and 92.18%,respectively.Conclusion The TCR of Vα6 or Vβ13 subfamily T cell clones have high homology in the 3-D spatial structures from the PBMCs of 2 cases of DLBCL patients,suggesting that they might recognize similar tumor associated antigen epitope.