目的： 探讨HLAⅠ类分子及MHCⅠ类链相关分子(MICA/MICB)在人鼻咽癌细胞株CNE2及多药耐药细胞株CNE2/DDP的表达及其对NK细胞杀伤活性的影响。方法： 流式细胞仪检测CNE2和CNE2/DDP细胞表面HLA Ⅰ类分子和MICA/MICB的表达情况；LDH释放法测定3例健康者的NK细胞在不同效靶比时对CNE2、CNE2/DDP细胞的杀伤活性；效靶比10∶1时，用抗HLAⅠ类分子单抗(W6/32)和抗MICA/MICB单抗(BAMO-1)分别封闭HLAⅠ类分子和MICA/MICB，观察NK细胞杀伤CNE2、CNE2/DDP细胞活性的变化。结果： CNE2/DDP细胞表面HLA Ⅰ类分子和MICA/MICB的表达均较CNE2细胞明显减少(Ｐ<0.01)。NK细胞对CNE2、CNE2/DDP细胞的杀伤活性在效靶比5∶1时分别是(9.37±2.14) %、(4.37±063 )%;效靶比10∶1时分别是(27.14±1.82)%、(15.79±2.87)%;效靶比20∶1时分别是(36.40±4.28)%、(26.20±418)%;效靶比30:1时分别是(54.67±2.80)% 、(40.29±2.73)%。各效靶比时NK细胞对CNE2、CNE2/DDP细胞的杀伤活性与HLAⅠ类分子和MICA/MICB相关，NK细胞对CNE2/DDP细胞的杀伤活性明显低于CNE2细胞(Ｐ<0.01)。效靶比10∶1时，W6/32明显增强NK细胞对CNE2、CNE2/DDP细胞的杀伤活性(Ｐ<0.01)，BAMO 1明显抑制NK细胞对CNE2、CNE2/DDP细胞的杀伤活性(Ｐ<0.01)。结论： HLA Ⅰ类分子和MICA/MICB在CNE2、CNE2/DDP的表达差异影响着NK细胞的杀伤活性，MICA/MICB在多药耐药肿瘤细胞的低表达导致耐药肿瘤细胞对NK细胞杀伤敏感性下降。

Objective: To analyze the expression of HLA class Ⅰ molecules and MHC classⅠ related chain A and B (MICA/MICB) in human nasopharyngeal carcinoma cell line (CNE2) and multi-drug resistant nasopharyngeal carcinoma cell line (CNE2/ DDP), and to assess their influence on NK cell-mediated lysis.Methods: Expression of HLA classⅠ molecules and MICA/MICB on the surface of CNE2 and CNE2/DDP cell lines was analyzed by flow cytometry. Cytotoxicity of NK cells (isolated from 3 healthy persons) against CNE2 and CNE2/DDP cells were detected by LDH releasing assay at different effect-to-target cell ratios (E∶T). In blocking experiments, anti-MHC class Ⅰ monoclonal antibody (mAb) (W6/32, a pan anti-HLA class Ⅰ antibody) and anti-MHC class I chain related molecules mAb (BAMO-1, specificly against MICA and MICB) were added to the target cells at a E∶T ratio of 10∶1. Results:It was found that the expression of HLA class Ⅰ molecules and MICA/MICB on CNE2 was higher than that on CNE2/DDP(Ｐ<0.01). Cytotoxicity of NK cells against CNE2 and CNE2/DDP cells was (9.37±2.14) %, (4.37±0.63 )% at E∶T ratio of 5∶1, (27.14±1.82)%, (15.79±2.87)% at E∶T ratio of 10∶1, (36.40±4.28)%, (26.20±4.18)% at E∶T ratio of 20∶1, and (54.67±2.80)%, (40.29±2.73)% at E∶T ratio of 30∶1, respectively. NK cells displayed higher cytotoxicity against parental CNE2 cells than multi-drug resistant CNE2/DDP cells(P<0.01). Expression of HLA classⅠ molecules and MICA/MICB on CNE2, CNE2/DDP cells was correlated with NK cell-mediated lysis. Blocking experiments confirmed that the killing of CNE2, CNE2/DDP cells was efficiently inhibited by BAMO-1, whereas efficiently increased by W6/32. Conclusion: Low expression of MICA/MICB in multi-drug resistant tumor cell lines leads to reduction of their susceptibility to NK lysis.