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目的探讨脐带血和健康成人外周血TCR Vγ和Vδ基因谱系的分布情况及克隆性特点。方法利用RT-PCR法检测16例脐带血和10例健康成人外周血单个核细胞TCRVγ(Ⅰ～Ⅲ)和Vδ(1～8)各亚家族的表达,了解各亚家族的分布和利用情况;阳性的PCR产物进一步经荧光素标记和基因扫描分析其CDR3长度,了解T细胞的克隆性。2例成人胸腺组织作为对照。结果脐带血T细胞的Vγ基因表达主要集中在VγⅠ和VγⅡ,而Vδ基因则平均表达(4.63±1.03)个亚家族,主要集中在Vδ1、2、3、8中表达。健康成人外周血T细胞除了1例不表达VγⅢ之外,其余均表达全部Vγ基因,而在Vδ基因中则平均表达(3.6±0.52)个亚家族,并以Vδ1、2和3为多见,Vδ4和Vδ5未能在外周血中检测到,而Vδ5和Vδ8的表达则明显低于脐带血(P=0.009,P=0.001);2例成人胸腺组织表达除Vδ4和Vδ6之外的其他Vγ和Vδ亚家族。基因扫描显示16例脐带血中有1例在VγⅠ和5例分别在Vδ2、Vδ4和Vδ6中出现寡克隆性,10例成人外周血中有9例在不同亚家族中出现克隆性T细胞,其余均呈多克隆性。结论脐带血TCRVγ和Vδ亚家族T细胞和健康成人外周血Vδ亚家族T细胞的分布均存在选择性,TCR Vδ亚家族在健康成人外周血中有一定的限制性,其出现克隆性T细胞的频率较脐带血高。
Objective To investigate the distribution and clonality of TCR Vγ and Vδ gene lineages in umbilical cord blood and healthy adult peripheral blood. Methods The expression of TCRVγ (Ⅰ ~ Ⅲ) and Vδ (1 ~ 8) subfamilies were detected by RT-PCR in 16 cases of umbilical cord blood and 10 cases of healthy adult human peripheral blood mononuclear cells to understand the distribution and utilization of each subfamily. Positive PCR products were further analyzed for CDR3 length by fluorescein labeling and gene scanning to understand the clonality of T cells. Two adult thymus tissues served as controls. Results The expression of Vγ gene in umbilical cord blood T cells mainly focused on VγⅠ and VγⅡ, while the expression of Vδ gene on average (4.63 ± 1.03) subfamilies was mainly concentrated in Vδ1,2,3,8. All of the peripheral blood T cells of healthy adults expressed all the Vγ genes except for one without VγⅢ expression and 3.6 ± 0.52 with the Vδ genes, Vδ5 and Vδδ were not detected in peripheral blood, while the expressions of Vδ5 and Vδ8 were significantly lower than those in umbilical cord blood (P = 0.009, P = 0.001). Other Vγ4 and Vδ6 were not expressed in 2 adult thymus tissues except Vδ4 and Vδ6 Vδ subfamily. Gene scan revealed that 1 of 16 cases of umbilical cord blood had oligoclonality in Vδδ, Vδδ and Vδδ in VγⅠ and 5 cases, and clonal T cells in 9 cases in 10 subfamilies Were polyclonal. Conclusion The distribution of TCRVγ and Vδ subfamily T cells in cord blood and Vδ subfamily T cells in peripheral blood of healthy adults are both selective. The TCR Vδ subfamily is restricted in peripheral blood of healthy adults. The appearance of clonal T cells Frequency higher than cord blood.