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不同T细胞克隆TCR分子的序列不同 ,所识别的抗原特异性也不同。其中第三互补决定区 (CDR3)变异最大 ,是TCR主要的抗原结合部位。本文采用荧光标记半定量PCR技术 ,用DNA测序仪作程序分析 ,了解猪细胞抗原致敏前后的人T细胞群和 5个T细胞系 2 4个TCRBV基因家族取用格局 ,并以TCRα链C区的基因片断作为内参对取用情况作定量估计。发现首次抗原致敏后培养 2周的T细胞除了BV2 4、BV8和BV10未能检测出 ,其它BV基因都有不同程度的取用。然而 ,5个细胞系的TCRBV基因呈现十分有限的取用格局 ,其中两个CD4+ T细胞系都取用BV12和BV14;3个CD8+ T细胞系中都优势取用BV1,有两个还取用BV19。CD4+ T细胞系和CD8+ T细胞系之间TCRBV无交叉取用 ,提示两类细胞识别的抗原表位存在差异。进一步用变性凝胶扫描分析上述T细胞系取用TCRBV中的CDR3的多样性 ,发现未经抗原致敏的T细胞BV的CDR3结构为多峰型且呈正态分布 ,表明涉及多种结构不同的细胞克隆 ;而抗原特异性T细胞系CDR3除了一个CD8+ T细胞系BV1有两个主峰外其它无例外地都显示单峰或者仅一个主峰 ,这从另一个角度证明建系T细胞的单克隆性。
Different T cell clones have different sequences of TCR molecules and recognize different antigen specificities. The third complementarity determining region (CDR3) has the largest variation and is the major antigen-binding site of TCR. In this study, fluorescent-labeled semi-quantitative PCR was used to analyze the sequence of 24 TCRBV gene families in human T cell population before and after sensitized with porcine antigen and 24 TCRBV gene families by T-DNA sequencing. Region of the gene fragment as a reference for the use of quantitative estimates. It was found that T cells cultured for 2 weeks after the first antigen sensitization could not be detected except for BV2 4, BV8 and BV10, and other BV genes were used in varying degrees. However, the TCRBV genes of the five cell lines showed a very limited pattern of access, with BV12 and BV14 for both CD4 + T cell lines; BV1 for both CD8 + T cell lines and BV1 for two BV19. No cross-referencing of TCRBV between the CD4 + T cell line and the CD8 + T cell line suggests that there are differences between the epitopes recognized by both cell types. Furthermore, we further analyzed the diversity of CDR3 in TCRBV by denaturing gel scanning. We found that the CDR3 structure of non-antigen-sensitized T cells BV is multimodal and has a normal distribution, indicating that it involves multiple structures Whereas the antigen-specific T cell line CDR3 showed a single peak or only one main peak with exception of two main peaks of BV1 except for one of the CD8 + T cell lines, proving from another perspective that monoclonal antibodies to T cells Sex.