Heidenreich S, Gong J H, Schmidt A, Nain M, Gemsa D
Institute of Immunology, University of Marburg, West Germany.
J Immunol. 1989 Aug 15;143(4):1198-205.
The macrophage-activating properties of murine recombinant granulocyte-macrophage (GM)-CSF were studied in murine peritoneal macrophages with respect to metabolism, endocytosis, PGE2 and TNF-alpha release, and tumor cytotoxicity. GM-CSF was found to be a potent stimulus for RNA and protein synthesis, glucose consumption, pinocytosis, and FcR-independent phagocytosis. Macrophages were activated by GM-CSF to kill TNF-alpha-insensitive Eb lymphoma cells but failed to generate cytotoxicity against TNF-alpha-sensitive L929 cells. Although GM-CSF alone was incapable of stimulating TNF-alpha release, it primed macrophages for elevated TNF-alpha production in response to IFN-gamma plus LPS. The priming effect of GM-CSF disappeared upon longer incubation (greater than 12 h) and was followed by a strongly reduced responsiveness to stimuli that release TNF-alpha. Late-stage suppression could be reverted by treatment with the cyclooxygenase blocker indomethacin, and GM-CSF-induced priming for enhanced TNF-alpha release was entirely restored. The responsible arachidonic acid product mediating suppression was found to be PGE2, because 1) GM-CSF-primed macrophages released enhanced amounts of PGE2 and 2) indomethacin-restored macrophages were again suppressed when exogenous PGE2 was added back in amounts produced by GM-CSF-primed macrophages. Although GM-CSF potently induced TNF-alpha gene transcription by 20 h of treatment, PGE2 interfered with translation into the secreted TNF-alpha protein. These data show that GM-CSF is capable of priming for the enhanced release of two factors, initially for TNF-alpha and subsequently for PGE2. The temporally delayed generation of these two mediators suggests an autoregulatory circuit in which the later produced PGE2 limits GM-CSF-induced macrophage activation.
研究了小鼠重组粒细胞-巨噬细胞（GM）-集落刺激因子对小鼠腹膜巨噬细胞的巨噬细胞激活特性，涉及代谢、内吞作用、前列腺素E2（PGE2）和肿瘤坏死因子-α（TNF-α）释放以及肿瘤细胞毒性。发现GM-CSF是RNA和蛋白质合成、葡萄糖消耗、胞饮作用以及不依赖Fc受体的吞噬作用的有效刺激物。GM-CSF激活巨噬细胞以杀死对TNF-α不敏感的Eb淋巴瘤细胞，但对TNF-α敏感的L929细胞未能产生细胞毒性。尽管GM-CSF单独不能刺激TNF-α释放，但它使巨噬细胞对干扰素-γ加脂多糖产生的TNF-α生成增加产生预激作用。GM-CSF的预激作用在较长时间孵育（大于12小时）后消失，随后对释放TNF-α的刺激的反应性大幅降低。晚期抑制可通过用环氧化酶阻滞剂吲哚美辛治疗来逆转，GM-CSF诱导的增强TNF-α释放的预激作用完全恢复。发现介导抑制作用的花生四烯酸产物是PGE2，原因如下：1）GM-CSF预激的巨噬细胞释放的PGE2量增加；2）当重新添加GM-CSF预激的巨噬细胞产生量的外源性PGE2时，吲哚美辛恢复的巨噬细胞再次受到抑制。尽管GM-CSF在处理20小时时强烈诱导TNF-α基因转录，但PGE2干扰其翻译成分泌型TNF-α蛋白。这些数据表明，GM-CSF能够引发两种因子的增强释放，最初是TNF-α，随后是PGE2。这两种介质在时间上的延迟产生表明存在一种自动调节回路，其中后期产生的PGE2限制了GM-CSF诱导的巨噬细胞激活。
