Oehler J R, Herberman R B
Int J Cancer. 1978 Feb 15;21(2):221-9. doi: 10.1002/ijc.2910210214.
Treatment of rats with high doses of hydrocortisone, X-irradiation, or cyclophosphamide had a suppressive effect on natural cytotoxicity in vivo. However, when rats were given poly I:C after any of these agents, the levels of NK activity were similar to those in normal rats which had been given poly I:C alone. To explain these findings, we have postulated that a population of pre-NK cells, resistant to hydrocortisone, cyclophosphamide and X-irradiation was induced by poly I:C to become cytotoxic NK cells. Treatment of rats with silica, in doses that had no effect on proliferative responses of host lymphocytes to Con A in vitro, sharply diminished NK activity. With this agent, the boosting effect of poly I:C, although still detectable, was diminished. Since there is little if any indication that NK cells are phagocytic, these data suggest that phagocytes may play a role in maintaining high levels of NK activity in vivo and, further, may be involved in the mechanism by which natural cytotoxicity is boosted by poly I:C. Adult thymectomized rats had easily detectable levels of natural reactivity and the response to poly I:C was unimpaired, indicating a lack of thymic dependence for boosting as well as for spontaneous levels of NK activity.
用高剂量氢化可的松、X射线照射或环磷酰胺处理大鼠，对其体内的自然细胞毒性有抑制作用。然而，在给予这些试剂中的任何一种后再给大鼠注射聚肌胞苷酸（poly I:C），自然杀伤（NK）活性水平与单独给予聚肌胞苷酸的正常大鼠相似。为了解释这些发现，我们推测聚肌胞苷酸诱导了一群对氢化可的松、环磷酰胺和X射线照射有抗性的前NK细胞成为具有细胞毒性的NK细胞。用二氧化硅处理大鼠，剂量对宿主淋巴细胞体外对刀豆蛋白A的增殖反应没有影响，但显著降低了NK活性。使用这种试剂后，聚肌胞苷酸的增强作用虽然仍可检测到，但有所减弱。由于几乎没有迹象表明NK细胞具有吞噬作用，这些数据表明吞噬细胞可能在维持体内高水平NK活性中起作用，并且进一步可能参与聚肌胞苷酸增强自然细胞毒性的机制。成年胸腺切除大鼠具有易于检测到的自然反应水平，并且对聚肌胞苷酸的反应未受损，表明增强以及自发NK活性水平均缺乏胸腺依赖性。
