骨髓间充质干细胞对异体自然杀伤细胞调节作用的研究

本研究探讨骨髓间充质干细胞(MSC)对异基因自然杀伤细胞(NK)和NK-T细胞增殖和杀伤功能的影响。分离健康供者外周血单个核细胞,在抗人CD3单克隆抗体、IL-2和PHA诱导下培养扩增NK和NK-T细胞,用流式细胞术分析MSC共培养对扩增体系中NK和NK-T细胞比例的影响,MTT法观察MSC对NK细胞杀伤K562细胞的影响。结果表明:高密度MSC能抑制NK细胞的生成,MSC在0、1×105/ml和5×105/ml时培养体系中NK细胞的比例分别为(16.9±4.6)%、(14.0±8.6)%和(6.4±4.6)%,统计学分析有显著意义(P<0.05),但MSC在低密度条件下(1×104/ml)可促进NK细胞的生成,NK细胞比例可达(20.9±7.1)%,与无MSC相比有统计学意义(P<0.05)。MSC剂量的变化对共培养体系中NK-T细胞的比例无明显影响。MTT法检测结果显示,共培养体系中K562细胞杀伤作用与NK细胞比例平行,不同密度MSC可能通过对NK细胞比例的双向调节而调节NK细胞对K562细胞的杀伤作用。结论:MSC在低剂量时可促进NK细胞形成并增强其肿瘤杀伤作用,但在高剂量时可抑制NK细胞形成从而抑制其对肿瘤细胞的杀伤作用。

Bone marrow-derived mesenchymal stem cells regulate the proliferation and activity of natural killer cells

This study was aimed to explore the effect of bone marrow-derived mesenchymal stem cells (MSC) on proliferation and activity of natural killer (NK) and NK-T cells. MSC was co-cultured with peripheral mononuclear cells from healthy donors in presence of IL-2, phytohemagglutinin (PHA) and mouse anti-human CD3 McAb (culture condition known to expand NK cells). The ratio of NK cells and NK-T cells was measured by flow cytometry and the effect of MSC on killing activity of NK cells against K562 cells was detected by MTT method after co-cultured with different densities of MSC. The results showed that MSC inhibited the production of NK cells in a dose-dependent manner generally. At the densities of 0, 1 × 10(5) and 5 × 10(5)/ml, the ratios of NK cells in the co-culture conditions were (16.9 ± 4.6), (14.0 ± 8.6) and (6.4 ± 4.6), respectively (P < 0.05). However, MSC could promote the formation of NK cells at lower MSC density (1 × 10(4)/ml), the ratio of NK cells reached to (20.9 ± 7.1), which was higher than that of culture condition without MSC (P < 0.05). The different densities of MSC in the co-culture conditions had no much influence on the ratio of NK-T cells (P > 0.05). MTT assay showed that the killing activity of suspended cells in co-culture system against K562 cells was parallel with the ratio of NK cells. Different densities of MSC regulated bidirectionally killing activity of NK to K562 cells by regulating bidirectionally ratio of NK cells. It is concluded that the MSC can promote the formation of NK cells and enhance its activity against tumor cells in the lower doses, while suppress the formation of NK cells and attenuate its tumor-killing effect in higher dose condition.