体外诱导人脐血树突状细胞介导T细胞抗白血病的细胞毒性效应研究

为了研究脐血淋巴细胞能否在体外培养成为特异性杀伤白血病细胞的杀伤性T细胞(CTL),联合细胞因子体外诱导脐血单个核细胞分化为树突状细胞(DC),再吞噬凋亡白血病细胞并将其抗原呈递给相同脐血的T淋巴细胞,得到杀伤性T细胞。用形态学及流式细胞术检测DC。CTL细胞的杀伤功能用乳酸脱氢酶(LDH)释放法测定。结果表明:12份脐血标本均可培养出形态典型的DC,DC的表面标志CD1a 、HLA DR 、CD86 、CD83 表达水平显著升高(P<0.05)。CTL可以杀伤未经培养的白血病细胞(效∶靶=50∶1对AML细胞的平均杀伤率为44.76±17.42%,对ALL细胞的平均杀伤率为8.50±4.25%),对相同患者缓解期的骨髓细胞杀伤率极低。结论: 在外体应用多种细胞因子刺激可诱导脐血单个核细胞分化成典型的DC;负载有白血病抗原的DC可诱导同一脐血的淋巴细胞生成白血病特异的杀伤性T细胞(CTL),所得CTL可特异性杀伤未经培养的白血病细胞而不严重伤害相同患者缓解期的骨髓细胞。

Ex vivo induction of Anti-leukemia Cytotoxic T Cell Effect by Dendritic Cells from Human Umbilical Cord Blood Cell Origin

To explore the possibility of in vitro induction of cord blood cell-derived lymphocytes into cytotoxic T lymphocytes (CTL) with anti-leukemia specificity, umbilical cord blood (UCB)-derived mononuclear cells were cultured with multiple cytokines to generate dendritic cells (DC) in vitro. Leukemia cells were irradiated with (137)Cs and activated by premature cytokines. The characteristics of maturation of DC were evaluated through morphology examination and flow cytometry. DC pulsed with leukemic antigens were co-cultured with lymphocytes. Cytotoxicity of the CTL to corresponding leukemic cells was measured with lactate dehydrogenase-release assay. The results showed that UCB-derived monocytes could be induced into typical DC in all of the 12 samples. Expression of immunological markers such as CD1a(+), HLA-DR(+), CD86(+), CD83(+) on DC were significantly up-regulated (P < 0.05). DC presenting leukemic antigens generated leukemia-specific CTL with a killing rate of (44.76 +/- 17.42)% at the E:T ratio of 50:1 against AML cells and a killing rate of (8.50 +/- 4.25)% at the E:T ratio of 50:1 against ALL cells. Whereas, these CTL present almost no killing effect on the mononuclear cells collected from the same patients in complete remission phase. It is concluded that (1) it is possible to induce UCB-derived monocytes into mature DC with typical morphology. (2) Cord blood derived mature DC presenting leukemia antigen can generate leukemia-specific CTL with vigorous cytotoxic activity against the same leukemia blasts and low killing activity against bone marrow cells of the same patients in complete remission phase.