同种异体NK细胞对AML细胞体外杀伤活性及初步机制

Cytotoxicity of allogenetic natural killer cells against AML cells and molecular mechanism

目的探讨同种异体自然杀伤细胞(NK细胞)对急性髓系白血病(AML)细胞株KG1a的杀伤活性及其分子机制。方法以NK敏感的K562细胞株为对照,免疫磁珠法分离5例健康志愿者NK细胞,乳酸脱氢酶(LDH)释放法测定在不同效靶比时NK细胞对KG1a细胞的杀伤活性,并用流式细胞仪检测KG1a细胞表面人类白细胞抗原I(HLA-I)类分子和NKG2D的配体主要组织相容性复合体(MIC)A/B、ULBP1-3的表达情况。结果效靶比1∶1、5∶1、10∶1、20∶1时NK细胞杀伤K562和KG1a细胞的活性不同,NK细胞对KG1a细胞的杀伤活性较K562细胞明显减低(P<0.01);K562细胞低表达HLA-I类分子,高表达NKG2D配体MIC可溶性Ⅰ类分子相关蛋白A(MICA)、MICA有亲源性的蛋白(MICB)、ULBP1、ULBP2、ULBP3,而KG1a细胞高表达HLA-I类分子,低表达NKG2D配体MICA、MICB、ULBP1、ULBP2、ULBP3。结论同种异体NK细胞对AML细胞株KG1a的杀伤率低于K562细胞;其杀伤率不同的分子基础与其分子表面配体表达差异和HLA-I分子表达率不同有关。

Objeetive To observe the cytotoxicity of allogenetic natural killer cellsagainst human acute myelocytic leukemia（AML） KGla cell line and its molecular mechanism.Methods The natural killer（NK） cells were isolated from 5 healthy individuals using magnetic cell sorting.The inhibitory effects of cytotoxicity of allogenetic NK cells against human acute myelogenous leukemia KGla cell line were measured by LDH re-lease assay.The expression of natural killer group 2 member D（NKG2D） ligauds（MICA/B,ULBP1,ULBP2,and ULBP3） and human leukocyte antigen（HLA） class I molecules on KG1a cells were assayed by flow cytometery.Results The inhibited the growth rate of KG1a vary with differ-ent effector-to-target.Conclusion NK cells inhibits the growth of KGla cells and up-regulated the expression of NKG2D ligands,and en-hances the sensitivity of KG1 cells to the cytotoxicity of NK cells.