AML-M2a细胞诱导自体及异体克隆性增殖T细胞及其特异性细胞毒性作用的研究

目的:了解急性粒细胞白血病(AML)M_2a细胞诱导自体及异体T细胞受体(TCR)Vβ亚家族T细胞克隆性增殖情况及其细胞毒性。方法:采用混合淋巴细胞/肿瘤细胞培养(MLTC)方法,用M_2a细胞体外诱导正常人和M_2a患者自体的外周血T细胞,用RT-PCR扩增经MLTC获得的自体和异体T细胞的24个TCRVβ亚家族基因的互补决定区(CDR3),阳性产物进一步经基因扫描分析确定M_2a细胞诱导的T细胞克隆性特点。同时用MTT法对淋巴细胞因子激活的杀伤细胞(LAK细胞)和MLTC获得的T细胞进行细胞毒性分析。结果:M_2a细胞诱导的自体及异体T细胞均出现了4-17个TCRVβ亚家族的优势表达,部分表达的Vβ亚家族T细胞具有克隆性增殖的特点。MLTC的不同时期和不同个体来源对TCRVβ亚家族T细胞表达及克隆性增殖有所影响。与LAK细胞相比,MLTC获得的T细胞以CD8⁺T细胞为主,对M_2a细胞具有较高的特异性细胞毒性作用。结论:MLTC获得的TCRVβ亚家族克隆性T细胞是自体和异体T细胞对M_2a细胞刺激所产生的一种特异性细胞免疫反应。M_2a细胞诱导后的T细胞对M_2a细胞具有特异性细胞毒性作用。

Clonal expansion and specific cytotoxicity of autologous or allogeneic T cells induced by M2a cells

AIM: To investigate clonal expansion and specific cytotoxicity of TCR Vβ subfamily T cells from acute myelogenous leukemia M_2a subtype (AML-M_2a)patients and normal individuals induced by AML-M_2a cells, respectively. METHODS: Complementarity determining region 3(CDR3) of TCR β with variable region genes was amplified in autologous or allogeneic T cells from mixed lymphocyte and tumor culture (MLTC) using RT-PCR. The positive products were further analyzed to identify the clonality of T cells by genescan. The specific cytotoxicity of T cells was analyzed by MTT. RESULTS: T cells from both M_2a patients and normal individuals after MLTC showed high response to M_2a cells with 4-17 TCR Vβ subfamily dominant utilization, one or two clonal expansion of T cells were identified in some predominant TCR Vβ subfamilies. Difference of distribution and clonal expansion of TCR Vβ subfamily T cells were related to source of T cells and the phase during MLTC. Compared with LAK cell, most of T cells from MLTC were CD3⁺CD8⁺T cells with higher and more specific cytoxicity to the induced cells, M_2a cells, but not HL60 or K562 cell line. CONCLUSION: Clonal expansion of TCR Vβ subfamily T cells stimulated selectively by M_2a cells may be a specific immune response of autologous and allogeneic T cells to M_2a cells associated antigen. The T cells induced by M_2a cells have the ability of specific cytoxicity to the AML-M_2a cells.