Blood Services Group, Health Sciences Authority, Singapore.
Exp Hematol. 2011 Sep;39(9):904-14. doi: 10.1016/j.exphem.2011.06.003. Epub 2011 Jun 13.
Interleukin (IL)-15 is a promising novel cytokine for natural killer (NK) cell activation and survival. We studied the effects of IL-15 compared to IL-2 on NK cells in long-term cultures for clinical translation.
CD56(+)CD3(-) NK cells were expanded with IL-2 or IL-15 for 2 to 4 weeks within lymphokine-activated killer (LAK) cell cultures (LAK-NK) in serum-enriched AIM V or CellGro Stem Cell Growth Medium (SCGM). Cell growth, viability, and NK cell content were monitored and cytotoxicity assessed in a flow cytometric cytotoxicity assay.
IL-15 (100-1000 U/mL) could replace IL-2 (1000 U/mL) in AIM V cultures to achieve efficient LAK cell expansion. However, IL-15-stimulated LAK cells exceeded cytotoxicity of IL-2-stimulated LAK cells against K562, notably at later culture points. In the powerful CellGro SCGM, LAK cells expanded over 28 days an average of 905-fold ± 320-fold standard error of the mean (SEM) for IL-2 (500 U/mL) and 484-fold ± 98-fold SEM for IL-15 (500 U/mL), and NK cells within such LAK cultures expanded an average of 2320-fold ± 975-fold SEM for IL-2 and 1084-fold ± 309-fold SEM for IL-15. Importantly, such IL-15-activated LAK-NK cells retained enhanced cytotoxicity at later culture points against K562 as well. IL-15-stimulated effectors were also highly cytotoxic against hematological targets MOLT-4 and KU812 and nontoxic against autologous nonmalignant cells. Interestingly, IL-15-LAK-NK cells showed overall significant upregulation of the main activating and inhibitory NK cell receptors after long-term cytokine stimulation.
Our results demonstrate the potential for IL-15 to support large-scale expansion of clinical-grade LAK-NK effectors, which could retain enhanced longer-term potency and preserve activation receptors in therapy of hematological malignancies. Protocols are readily clinically translatable.
白细胞介素（IL）-15 是一种有前途的新型细胞因子，可用于自然杀伤（NK）细胞的激活和存活。我们研究了与 IL-2 相比，IL-15 对长期培养中的 NK 细胞的影响，以进行临床转化。
CD56(+)CD3(-)NK 细胞在富含血清的 AIM V 或 CellGro 干细胞生长培养基（SCGM）中进行淋巴因子激活的杀伤（LAK）细胞培养（LAK-NK），用 IL-2 或 IL-15 培养 2 至 4 周。监测细胞生长、活力和 NK 细胞含量，并通过流式细胞术细胞毒性测定评估细胞毒性。
IL-15（100-1000 U/mL）可替代 AIM V 培养中的 IL-2（1000 U/mL），以实现高效的 LAK 细胞扩增。然而，与 IL-2 刺激的 LAK 细胞相比，IL-15 刺激的 LAK 细胞对 K562 的细胞毒性明显更高，尤其是在较晚的培养点。在强大的 CellGro SCGM 中，LAK 细胞在 28 天内平均扩增 905 倍±320 倍标准误差（SEM），对于 IL-2（500 U/mL）和 484 倍±98 倍 SEM 对于 IL-15（500 U/mL），并且此类 LAK 培养物中的 NK 细胞平均扩增 2320 倍±975 倍 SEM 对于 IL-2 和 1084 倍±309 倍 SEM 对于 IL-15。重要的是，这种 IL-15 激活的 LAK-NK 细胞在后期培养点也保留了对 K562 的增强细胞毒性。IL-15 刺激的效应物对血液学靶标 MOLT-4 和 KU812 也具有高度细胞毒性，而对自身非恶性细胞无毒。有趣的是，IL-15-LAK-NK 细胞在长期细胞因子刺激后表现出主要激活和抑制性 NK 细胞受体的总体显著上调。
我们的结果表明，IL-15 有可能支持临床级别的 LAK-NK 效应物的大规模扩增，这些效应物在治疗血液系统恶性肿瘤时可以保留增强的长期效力并保留激活受体。方案易于临床转化。
