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

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(CD3CDl6 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.

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

OBJECTIVE: To study the cytotoxic effect of allogenetic natural killer (NK) cells in vitro on human CD34+ acute myelogenous leukemia cells. METHODS: CD34 expression on acute myelogenous leukemia KG1a cells was detected by flow cytometry. KG1a 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 KG1a cells in the co-culture, and the inhibition rate of the KG1a 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 KG1a 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 KG1a 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 KG1a 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.