Potassium channels mediate killing by human natural killer cells.
Potassium channels mediate killing by human natural killer cells.
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DOI：
10.1073/pnas.83.2.451
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发表时间：
1986
影响因子：
11.1
通讯作者：
L. Schlichter;N. Sidell;S. Hagiwara
中科院分区：
文献类型：
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作者：
L. Schlichter;N. Sidell;S. Hagiwara
外周血中的人自然杀伤（NK）细胞自发地识别并杀死多种靶细胞。有人认为，离子通道参与了杀伤过程，因为有一个钙依赖性阶段，因为杀伤预敏化细胞毒性T淋巴细胞，这在许多方面类似于NK杀伤，是与靶细胞中的K和Na转运的变化。然而，没有直接证据表明NK细胞或其靶细胞中存在离子通道。利用全细胞膜片钳技术，我们在NK细胞上发现了电压依赖性钾电流。钾通道阻断剂4-氨基吡啶和奎尼丁以及传统的钙通道阻断剂维拉帕米和Cd 2+以剂量依赖性方式降低K+电流。我们测试了离子通道阻滞剂对两种常用靶细胞系的杀伤作用：K562，来源于人髓性白血病，和U937，来源于人组织细胞白血病。杀伤K562靶细胞，在一个标准的51铬释放测定，抑制维拉帕米，奎尼丁，镉2+，和4-氨基吡啶的浓度相当的剂量依赖性的方式，阻断NK细胞中的K+电流。在K562靶细胞中，仅发现电压依赖性Na+电流，并且其被对杀伤没有影响的浓度的河豚毒素阻断。两种离子通道阻断剂奎尼丁和维拉帕米也能抑制U937靶细胞的杀伤。在该细胞系中，仅发现与NK细胞中的K+电流类似的小的K+电流。我们没有发现靶细胞或NK细胞中Ca 2+电流的任何证据;因此，我们的结果不能解释杀伤的Ca依赖性。我们的研究结果表明，NK细胞中存在K通道，并且这些通道在杀伤过程中起着必要的作用。相反，靶细胞中的内源性通道类型可能不是决定靶细胞对自然杀伤敏感性的因素。
Human natural killer (NK) cells in peripheral blood spontaneously recognize and kill a wide variety of target cells. It has been suggested that ion channels are involved in the killing process because there is a Ca-dependent stage and because killings by presensitized cytotoxic T lymphocytes, which in many respects resembles NK killing, is associated with changes in K and Na transport in the target cell. However, no direct evidence exists for ion channels in NK cells or in their target cells. Using the whole-cell variation of the patch-clamp technique, we found a voltage-dependent potassium (K+) current in NK cells. The K+ current was reduced in a dose-dependent manner by the K-channel blockers 4-aminopyridine and quinidine and by the traditional Ca-channel blockers verapamil and Cd2+. We tested the effects of ion-channel blockers on killing of two commonly used target cell lines: K562, which is derived from a human myeloid leukemia, and U937, which is derived from a human histiocytic leukemia. Killing of K562 target cells, determined in a standard 51Cr-release assay, was inhibited in a dose-dependent manner by verapamil, quinidine, Cd2+, and 4-aminopyridine at concentrations comparable to those that blocked the K+ current in NK cells. In K562 target cells only a voltage-dependent Na+ current was found and it was blocked by concentrations of tetrodotoxin that had no effect on killing. Killing of U937 target cells was also inhibited by the two ion-channel blockers tested, quinidine and verapamil. In this cell line only a small K+ current was found that was similar to the one in NK cells. We could not find any evidence of a Ca2+ current in target cells or in NK cells; therefore, our results cannot explain the Ca dependence of killing. Our findings show that there are K channels in NK cells and that these channels play a necessary role in the killing process. In contrast, the endogenous channel type in the target cell is probably not a factor in determining target cell sensitivity to natural killing.