Nettelnbreker E, Zeidler H, Bartels H, Dreses-Werringloer U, Däubener W, Holtmann H, Köhler L
Division of Rheumatology, Medical School, Hannover, Germany.
J Med Microbiol. 1998 Feb;47(2):141-9. doi: 10.1099/00222615-47-2-141.
Inoculation of phorbol ester-differentiated U937 cells as a model for human macrophages with Chlamydia trachomatis of the urogenital serovar K resulted in a persistent infection, with maximal growth at day 7, until day 10 post-infection. At these times inclusion bodies were present in 0.5-2% of the cells. Typical inclusion bodies containing elementary bodies and reticulate bodies were observed by electron microscopy. Furthermore, single chlamydial particles resembling atypical elementary or intermediate bodies were identified in the cytoplasm in > 80% of the host cells. IFN-gamma exerts antichlamydial activity in epithelial and fibroblastoid cells, but the infection of U937 cells by C. trachomatis was not affected by IFN-gamma. The activity of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) was not detected in untreated or in IFN-gamma-treated or chlamydiae-infected or mock-infected U937 cells. The presence of atypical persisting chlamydiae and the lack of IDO expression in U937 cells indicates that the development of these atypical bacteria is independent from IFN-gamma-mediated tryptophan deprivation and other IFN-gamma-mediated effects. Evaluation of persistently infected cells revealed that the expression of the chlamydial major outer-membrane protein, heat-shock protein (hsp60) and lipopolysaccharide (LPS) antigens was not significantly altered in the course of the culture. An intense staining of the LPS on the surface of the host cells was demonstrated by immunofluorescence. The data show that phorbol ester-differentiated U937 cells restrict chlamydial growth strongly but not completely through a mechanism distinct from IDO-mediated tryptophan deprivation. The mechanisms of persistence of chlamydiae in monocytes, which differ considerably from those described for other cells, require further investigation.
用泌尿生殖血清型K的沙眼衣原体接种佛波酯分化的U937细胞作为人类巨噬细胞模型，导致持续感染，在感染后第7天生长达到最大值，直至第10天。此时，0.5%-2%的细胞中存在包涵体。通过电子显微镜观察到含有原体和网状体的典型包涵体。此外，在超过80%的宿主细胞的细胞质中鉴定出单个类似非典型原体或中间体的衣原体颗粒。IFN-γ在上皮细胞和成纤维样细胞中发挥抗衣原体活性，但沙眼衣原体对U937细胞的感染不受IFN-γ影响。在未处理的、IFN-γ处理的、衣原体感染的或模拟感染的U937细胞中均未检测到色氨酸降解酶吲哚胺2,3-双加氧酶（IDO）的活性。U937细胞中存在非典型持续存在的衣原体且缺乏IDO表达，这表明这些非典型细菌的发育独立于IFN-γ介导的色氨酸剥夺和其他IFN-γ介导的效应。对持续感染细胞的评估显示，衣原体主要外膜蛋白、热休克蛋白（hsp60）和脂多糖（LPS）抗原的表达在培养过程中没有显著改变。通过免疫荧光证明宿主细胞表面的LPS有强烈染色。数据表明，佛波酯分化的U937细胞通过一种不同于IDO介导的色氨酸剥夺的机制强烈但不完全地限制衣原体生长。衣原体在单核细胞中持续存在的机制与其他细胞中描述的机制有很大不同，需要进一步研究。
