Lin Chen, Chen Shaohua, Yang Lijian, Tan Yubo, Bai Xue, Li Yangqiu
Department of Microbiology and Immunology, Medical College of Jinan University, Guangzhou, PR China.
Hematology. 2007 Aug;12(4):325-30. doi: 10.1080/10245330701342342.
Examination of the T cell receptor (TCR) gene repertoire is important in the analysis of the immune status of models, because clonal expansion of T cells permits the identification of specific antigen responses of T cells. Little is known about T-cell immunity in the humanized NOD/SCID mouse model. TCR Vbeta repertoire usage and clonality were analyzed to investigate the distribution and clonal expansion of TCR Vbeta subfamily T cells in NOD/SCID mice transplanted with human cord blood (CB) hematopoietic stem cells. The NOD/SCID mice were sublethally irradiated ((60)Co, 300cGy) to eliminate residual innate immunity in the host. The experimental mice were transplanted intravenously with CB CD34(+) cells sorted by MACS. After 6 weeks, RNA was obtained from peripheral blood, bone marrow and thymus of the study animals. The gene expression and clonality of the TCR Vbeta repertoire were determined by RT-PCR and GeneScan techniques. A restricted range of TCR Vbeta usage was exhibited in the bone marrow of mice, which included TCR Vbeta 1, 2, 9, 13 and 19. Further, oligoclonal expression of some TCR Vbeta subfamilies (Vbeta9, 13, 19) was identified by GeneScan technique. To investigate the reason for oligoclonal expansion of the TCR Vbeta subfamily T cells from CB in mouse models, the T-cell culture with tissue-antigen of NOD/SCID mouse was performed in vitro. The cells from peripheral blood mononuclear cells and bone marrow, spleen, thymus in NOD/SCID mice were frozen and thawed, and used as tissue-antigen. CB mononuclear cells were separately cultured with the component from those murine cells for 15-20 days. Oligoclonal expression or oligoclonal trend of some TCR Vbeta subfamilies (Vbeta10, 11 and Vbeta2, 15, 16, 19) was detected in T cells after stimulation with tissue-antigen of NOD/SCID mouse. Interestingly, a similar clonal expansion of the TCR Vbeta11 subfamily was found in T cells cultured with peripheral blood, bone marrow and spleen respectively. The TCR Vbeta subfamily T cells could be reconstituted in humanized NOD/SCID mouse transplanted with CD34(+) cells from CB. The restricted expression and clonal expansion of some CB T cell clones may be induced by tissue-antigens of NOD/SCID mice.
T细胞受体（TCR）基因库的检测对于模型免疫状态的分析很重要，因为T细胞的克隆性扩增有助于识别T细胞的特异性抗原反应。关于人源化NOD/SCID小鼠模型中的T细胞免疫，人们了解甚少。分析TCR Vβ基因库的使用情况和克隆性，以研究移植了人脐血（CB）造血干细胞的NOD/SCID小鼠中TCR Vβ亚家族T细胞的分布和克隆性扩增。对NOD/SCID小鼠进行亚致死剂量照射（（60）Co，300cGy）以消除宿主体内残留的固有免疫。将通过磁珠分选的CB CD34（+）细胞静脉注射到实验小鼠体内。6周后，从研究动物的外周血、骨髓和胸腺中获取RNA。通过逆转录聚合酶链反应（RT-PCR）和基因扫描技术确定TCR Vβ基因库的基因表达和克隆性。小鼠骨髓中TCR Vβ的使用范围有限，包括TCR Vβ 1、2、9、13和19。此外，通过基因扫描技术鉴定出一些TCR Vβ亚家族（Vβ9、13、19）的寡克隆表达。为了研究小鼠模型中来自CB的TCR Vβ亚家族T细胞寡克隆扩增的原因，在体外用人源化NOD/SCID小鼠的组织抗原进行T细胞培养。将NOD/SCID小鼠外周血单个核细胞、骨髓、脾脏和胸腺中的细胞冻融后用作组织抗原。将CB单个核细胞分别与这些鼠细胞成分共培养15 - 20天。在用NOD/SCID小鼠组织抗原刺激后的T细胞中检测到一些TCR Vβ亚家族（Vβ10、11和Vβ2、15、16、19）的寡克隆表达或寡克隆趋势。有趣的是，在用外周血、骨髓和脾脏分别培养的T细胞中发现了TCR Vβ11亚家族类似的克隆性扩增。移植了来自CB的CD34（+）细胞的人源化NOD/SCID小鼠中可以重建TCR Vβ亚家族T细胞。一些CB T细胞克隆的有限表达和克隆性扩增可能是由NOD/SCID小鼠的组织抗原诱导的。
