目的:体外观察树突状细胞(dendritic cell,DC)联合细胞因子诱导的杀伤细胞(cytokine inducedkiller,CIK)对K562/A细胞株多药耐药基因mdr1表达的影响。方法:采集健康人的外周血,分离出单个核细胞(peripheral blood mononuclear cell,PBMC),在体外加入多种细胞因子经诱导生成DC及CIK细胞,以流式细胞仪检测其表面标志,将DC细胞内加入K562/A细胞裂解物致敏后,再与CIK细胞混合培养48小时。将致敏后的DC-CIK细胞与K562/A及K562分组培养后以荧光定量PCR检测其mdr1基因表达的情况,PBMC作为对照组。结果:RT-PCR中可见K562/A+DC-CIK组中mdr1 mRNA表达较K562/A明显降低,经荧光定量PCR观察到K562/A内mdr1 mRNA表达为K562的10.27倍、K562/A/PBMC略低于未处理的K562/A(P>0.05),K562/A/DC-CIK细胞中mdr1 mRNA含量较K562/A、K562/A/PBMC少(P<0.05)。DC-CIK细胞与细胞株混合培养后,mdr1基因表达较混合培养前明显降低。结论:实验数据显示DC-CIK可使耐药细胞株内mdr1基因表达下调。但K562与DC-CIK混合培养后该基因降低不明显,提示该基因在细胞中存在着基础表达,意义在于维持细胞内稳态。目前针对逆转白血病耐药的研究较少,需要多进行相关研究以拓宽细胞免疫治疗在逆转耐药领域的应用。DC-CIK是具有发展潜力的抗肿瘤方法。本实验将为下一阶段研究逆转耐药的机制提供依据,DC-CIK细胞免疫疗法有望成为逆转肿瘤耐药的新方法。 Objective: To observe the effect of dendritic cell (DC) and cytokine induced killer (CIK) on the expression of multidrug resistance gene mdr1 in K562 / A cell line in vitro. Methods: Peripheral blood was collected from healthy volunteers. Peripheral blood mononuclear cells (PBMCs) were isolated from human peripheral blood mononuclear cells (PBMC). DC and CIK cells were induced by adding various cytokines in vitro. The surface markers were detected by flow cytometry. K562 / A cell lysate was added to the cells and then mixed with CIK cells for 48 hours. After sensitized DC-CIK cells were cultured with K562 / A and K562 groups, the expression of mdr1 gene was detected by fluorescence quantitative PCR. PBMC served as the control group. Results: RT-PCR showed that mdr1 mRNA expression in K562 / A + DC-CIK group was significantly lower than that in K562 / A group. The expression of mdr1 mRNA in K562 / A was 10.27- The level of mdr1 mRNA in K562 / A / DC-CIK cells was lower than that in untreated K562 / A and K562 / A / PBMCs (P <0.05). After mixed culture of DC-CIK cells and cell lines, mdr1 gene expression was significantly lower than that before mixed culture. Conclusion: The experimental data show that DC-CIK can down-regulate mdr1 gene expression in drug-resistant cell lines. However, this gene was not significantly reduced after mixed culture of K562 and DC-CIK, suggesting that there is a basic expression of this gene in cells, the significance of which is to maintain the cell homeostasis. At present, there are few researches on drug resistance in reversing leukemia, and more studies are needed to broaden the application of cellular immunotherapy in the field of drug resistance reversal. DC-CIK is a promising anti-tumor method. This experiment will provide the basis for the study of the mechanism of reversal of drug resistance in the next stage. DC-CIK cell immunotherapy is expected to become a new method to reverse the drug resistance of tumor.