VISTA信号阻断对DC-CIK杀伤恶性肿瘤细胞的影响

Inhibition of DC-CIK VISTA signal for improving the anti-tumor effect of malignant tumor cells

目的探讨阻断树突状细胞联合细胞因子诱导的杀伤细胞(DC-CIK)表面T细胞激活抑制物免疫球蛋白可变区结构域(VISTA)抗原,抑制由VISTA信号活化引起的免疫负调节,对其杀伤恶性肿瘤细胞的活性的影响。方法采用流式细胞术分析DC-CIK与抗VISTA抗体的结合情况,用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)法检测DC-CIK对人慢性髓系白血病细胞株K562的杀伤效应。通过细胞计数及流式细胞术分析VISTA抗体对DC-CIK增殖和分化的影响。结果培养成熟的DC-CIK与抗VISTA抗体温育后,其抗体结合率可达(10.26±0.57)%。随着效应细胞(DC-CIK)与靶细胞(K562细胞)比例的增高,实验组(经抗VISTA抗体处理的DC-CIK)和对照组(未经处理的DC-CIK)的杀伤活性均显著增高;当效应细胞∶靶细胞为10∶1和20∶1时,实验组的杀伤活性分别为(77.3±6.8)%和(92.8±5.9)%,均明显高于对照组[(64.8±4.0)%、(81.8±5.4)%](P<0.01)。温育54 h后,实验组的细胞数明显高于对照组(P<0.01),为对照组的1.35倍。实验组CD3^+CD56^+自然杀伤性T细胞(NKT)比例为(35.12±2.13)%,明显高于对照组[(21.35±1.32)%](P<0.01)。结论阻断DC-CIK VISTA信号可促进DC-CIK的增殖和分化,增强其对肿瘤细胞的杀伤效应。

Objective To inhibit the antigen of anti-V-domain Ig suppressor of T cell activation(VISTA)antibody on dendritic cell-cytokine-induced killer cell(DC-CIK)and the down regulation due to VISTA signal activation,and to evaluate the anti-tumor effect of malignant tumor cells.Methods Anti-VISTA antibody on DCCIK was determined by flow cytometry.The killing activity of DC-CIK on human chronic myeloid leukemia cell line K562 was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT).The effect of anti-VISTA antibody on the proliferation and differentiation of DC-CIK was analyzed by cell count analysis and flow cytometry,respectively.Results After the incubation of mature DC-CIK with anti-VISTA antibody,the percentage of anti-VISTA antibody positive cells was(10.26±0.57)%.With the increasing of effector cells(DC-CIK)-to-target cells(K562)ratio,the killing activities in experimental group(DC-CIK cell treated with anti-VISTA antibody)and control group(untreated DC-CIK cell)were increased.When effector cells-to-target cells ratios of 10∶1 and 20∶1,the killing activities in experimental group were(77.3±6.8)%and(92.8±5.9)%,respectively,which were higher than those in control group[(64.8±4.0)%and(81.8±5.4)%](P<0.01).After incubation for 54 h,the cell number of experimental group was 1.35-time higher than that of control group(P<0.01).The percentage of CD3+CD56+natural killer T cells(NKT)in experimental group[(35.12±2.13)%]was higher than that in control group[(21.35±1.32)%](P<0.01).Conclusions The inhibition of DC-CIK VISTA signal can improve the antitumor effect of malignant tumor cells through the proliferation and differentiation of DC-CIK.