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目的 探讨肿瘤多药抗性细胞的免疫逃避机制。方法 利用特异性切割mdr1的核酶为工具，以表达Mdr1的耐药细胞株KBv200为靶细胞，采用脂质体转染技术，将含核酶的质粒pHβApr-1neo/5mR3及空载体pHβApr-1neo导入KBv200及其亲本KB细胞内，运用Northern-blotting、免疫组化方法观察核酶对mdr1 mRNA及P-gp的影响，运用流式细胞仪技术检测各种不同细胞亚株HLA-Ⅰ、HLA-Ⅱ、B7-1、B7-2的表达。 结果 含核酶的质粒pHβApr-1neo/5mR3及空载体pHβApr-1neo可以在KB、KBv200细胞中稳定表达，核酶可以特异性地切割mdr1，导致KBv200/5mR3的mdr1 mRNA含量下降，P 糖蛋白（P-gp）表达减低，各种不同细胞亚株均表达较强的HLA-Ⅰ类抗原，而HLA-Ⅱ、B7-1、B7-2的表达较低。各亚株HLA-Ⅰ表达无明显差异，但HLA-Ⅱ、B7-1、B7-2的表达变化较大，KB的HLA-Ⅱ、B7-1、B7-2的表达较KBv200强，经化疗药物作用后KB的HLA-Ⅱ、B7-2进一步表达增强，核酶逆转后，KBv200/5mR3 HLA-Ⅱ、B7-1、B7-2的表达趋于接近KB水平。 结论 mdr1-核酶在细胞内具有一定的逆转肿瘤多药抗性的生物学效应；多药耐药细胞和敏感株细胞有着不同的免疫逃避特点，与敏感株相比，KBv200较易逃避机体的免疫反应。
Objective To investigate the immune evasion mechanism of tumor multidrug resistant cells. Methods Mdr1-specific ribozyme was used as a tool to express Mdr1-resistant cell line KBv200 as target cells. Liposome-mediated transfection was used to amplify the plasmid pHβApr-1neo / 5mR3 and empty vector pHβApr-1neo Northern blotting and immunohistochemistry were used to observe the effect of ribozyme on mdr1 mRNA and P-gp in KB cells of KBv200 and its parental cells. Flow cytometry was used to detect the expression of HLA-Ⅰ and HLA- Ⅱ, B7-1, B7-2 expression. Results The ribozyme plasmid pHβApr-1neo / 5mR3 and the empty vector pHβApr-1neo were stably expressed in KB and KBv200 cells. The ribozyme could specifically cleave mdr1, leading to the decrease of mdr1 mRNA in KBv200 / 5mR3, P-gp) expression decreased, a variety of different cell sublines expressed strong HLA-Ⅰ antigen, while HLA-Ⅱ, B7-1, B7-2 expression is low. There was no significant difference in the expression of HLA-Ⅰ among the sub-strains, but the expression of HLA-Ⅱ, B7-1 and B7-2 changed greatly. The expression of KB-HLA-Ⅱ, B7-1 and B7-2 was stronger than KBv200. The expression of KBv200 / 5mR3 HLA-Ⅱ, B7-1 and B7-2 tended to be close to KB after the drug treatment. Conclusion The mdr1-ribozyme has a biological effect of reversing the multidrug resistance in the cells. Multidrug-resistant cells and sensitive cells have different immune evasion characteristics. Compared with the susceptible strains, KBv200 is easier to escape from the body immune response.