CHARACTERIZATION OF AN INDOLEAMINE 2,3-DIOXYGENASE INDUCED BY GAMMA-INTERFERON IN CULTURED HUMAN-FIBROBLASTS
CHARACTERIZATION OF AN INDOLEAMINE 2,3-DIOXYGENASE INDUCED BY GAMMA-INTERFERON IN CULTURED HUMAN-FIBROBLASTS
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DOI：
10.1089/jir.1986.6.267
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发表时间：
1986-06-01
期刊：
影响因子：
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通讯作者：
ECKEL, M
中科院分区：
文献类型：
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作者：
PFEFFERKORN, ER;REBHUN, S;ECKEL, M
我们以前曾观察到γ-干扰素（IFN-γ）抑制培养的人成纤维细胞内的弓形虫（Toxoplasma gondii）的生长，这种抑制作用与培养液中色氨酸的消失以及犬尿氨酸和N-甲酰犬尿氨酸的出现有关。在这份报告中，我们发现IFN-γ诱导人成纤维细胞中的吲哚胺2，3-双加氧酶将色氨酸转化为N-甲酰犬尿氨酸。在1至至少32 NIH参考单位/ml的范围内，该酶的诱导是IFN-γ浓度的函数。诱导也是时间的函数，在用IFN-γ处理培养物后8-24 h观察到吲哚胺2，3-双加氧酶的最大增加。用放线菌素D或放线菌酮处理培养物可抑制IFN-γ对吲哚胺2，3-双加氧酶的诱导，因此依赖于RNA和蛋白质的合成。IFN-γ诱导的吲哚胺2，3-双加氧酶似乎与其他降解色氨酸的哺乳动物酶不同。其对色氨酸的Km值比大鼠肝色氨酸2，3-双加氧酶低100倍，底物特异性比兔肠吲哚胺2，3-双加氧酶窄，产生犬尿氨酸的N-甲酰犬尿氨酸甲酰胺酶是一种组成型酶，IFN-γ处理人成纤维细胞后其活性没有进一步提高。IFN-γ诱导的吲哚胺2，3-双加氧酶似乎在IFN-γ在人成纤维细胞中的抗病毒活性中不起主要作用。
We have previously observed that gamma-interferon (IFN-γ) inhibited the growth of the intracellular protozoan parasiteToxoplasma gondiiin cultured human fibroblasts and that this inhibition was related to the disappearance of tryptophan from the medium with the concomitant appearance of kynurenine andN-formylkynurenine. In this report, we show that IFN-γ induced an indoleamine 2,3-dioxygenase in human fibroblasts that converts tryptophan toN-formylkynurenine. The induction of this enzyme was a function of IFN-γ concentration over the range of 1 to at least 32 NIH reference units/ml. The induction was also a function of time, with the greatest increase in indoleamine 2,3-dioxygenase seen 8–24 h after treatment of cultures with IFN-γ. The induction of indoleamine 2,3-dioxygenase by IFN-γ was inhibited by treatment of the cultures with either actinomycin D or cycloheximide, and thus was dependent on both RNA and protein synthesis. The indoleamine 2,3-dioxygenase induced by IFN-γ appeared to differ from other mammalian enzymes that degrade tryptophan. It had aKmfor tryptophan that was 100-fold lower than that for rat liver tryptophan 2,3-dioxygenase and its substrate specificity was narrower than that of rabbit intestine indoleamine 2,3-dioxygenase.N-Formylkynurenine formamidase, the enzyme that produces kynurenine, was a constitutive enzyme and its activity was not further increased by treatment of human fibroblasts with IFN-γ. The indoleamine 2,3-dioxygenase induced by IFN-γ did not appear to play a major role in the antiviral activity of IFN-γ in human fibroblasts.