同种异体NK细胞对CD34^+早期急性髓系白血病细胞的细胞毒效应

Cytotoxicity of allogenetic natural killer cells against CD34^+ acute myelogenous leukemia cells

目的探讨同种异体NK细胞对CD34+早期急性髓系白血病细胞的细胞毒效应。方法免疫磁珠法分离5例健康个体NK细胞,乳酸脱氢酶释放法测定不同效靶比时NK细胞对CD34+早期急性髓系白血病细胞KG1a的杀伤活性,甲基纤维素克隆形成实验检测NK细胞对KG1a细胞的克隆形成抑制率,同时与NK杀伤敏感细胞株K562比较。结果急性髓系白血病细胞株KG1a中CD34抗原表达率为(98.0±1.1)%,分选后的NK细胞(CD3-CD16+CD56+细胞)纯度为(93.2±3.7)%。不同效靶比时NK细胞对KG1a细胞均有杀伤活性,均能抑制其克隆形成。随着效靶比的增高,其杀伤活性和克隆抑制率随之增高(P<0.05)。同一效靶比时,NK细胞对KG1a的杀伤活性和克隆抑制率低于K562(P<0.05)。结论同种异体NK细胞对CD34+早期急性髓系白血病细胞具有细胞毒效应。

Objective To study the cytotoxic effect ofallogenetic natural killer （NK） cells in vitro on human CD34^＋ acute myelogenous leukemia cells. Methods CD34 expression on acute myelogenous leukemia KGla cells was detected by flow cytometry. KGla cells were co-cultured at different effector-to-target （E：T） ratios with NK cells isolated from 5 healthy individuals using magnetic cell sorting. Lactate dehydrogenase （LDH） release assay was employed to examine the cytolysis of KGla cells in the co-culture, and the inhibition rate of the KGla cell colony formation in methylcellulose was determined with K562 cells sensitive to NK cells as the control. Results A expression rate as much as （98.0±1.1）% was detected for CD34 antigen on KGla cells, and the isolated NK cells （CD3-CD16^＋CD56^＋ cells） had a purity of （93.2±3.7）% after magnetic cell sorting. Allogenetic NK cells exhibited obvious cytotoxicity and colony inhibition in vitro against KGla cells at different E：T ratios, and the effects were significantly enhanced as the E：T ratios increased （P〈0.05）. At the same E：T ratio, the cytotoxicity and colony inhibition rate of allogenetic NK cells against KGla cells was lower than those against K562 cells （P〈0.05）. Conclusion Allogenetic NK cells exhibit obvious cytotoxicity and colony formation against CD34^＋ acute myelogenous leukemia cells.