Yamamoto Y, Retzlaff C, He P, Klein T W, Friedman H
Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa 33612.
Clin Diagn Lab Immunol. 1995 Jan;2(1):18-24. doi: 10.1128/cdli.2.1.18-24.1995.
Cytokine production in macrophages infected by bacteria is critical for the course of infection. However, it is not known how infection of macrophages with opportunistic bacteria leads to cytokine production in different populations of cells. Since it is possible that cytokine genes may be differentially regulated by attachment rather than by active infection, the levels of various cytokine mRNAs were measured in alveolar macrophages (AMs), peritoneal resident macrophages (RMs), and peritoneally elicited macrophages (EMs) interacting with Legionella pneumophila by using cytochalasin D-treated macrophages and a newly developed quantitative reverse transcription-PCR procedure with high-performance liquid chromatographic analysis to determine cytokine mRNA formation. Increased levels of interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, and macrophage inflammatory protein 2 mRNAs were quantitated in the macrophages responding to L. pneumophila attachment in vitro. Using this technique, we showed that the three different macrophage populations responded differently to bacterial attachment. We found that the levels of IL-6 and granulocyte-macrophage colony-stimulating factor mRNAs induced by the attachment of L. pneumophila to AMs were significantly lower than the levels in RMs but similar to the levels in EMs. Furthermore, the levels of MIP-2 mRNA in the AMs were found to be higher than those in the RMs, but similar levels were found in EMs. IL-1 beta mRNA levels were higher in both AMs and RMs than in EMs, but tumor necrosis factor alpha levels were not different among the three macrophage populations examined. Thus, the responses of macrophages to bacterial attachment in terms of cytokine mRNA levels were readily quantitated by the reverse transcription-PCR assay. However, the results obtained showed different levels of responsiveness of distinct macrophage populations to L. pneumophila attachment, and this could be related to the characteristic nature of the macrophage type examined.
细菌感染巨噬细胞后细胞因子的产生对感染进程至关重要。然而，尚不清楚机会致病菌感染巨噬细胞如何导致不同细胞群体产生细胞因子。由于细胞因子基因可能受附着而非主动感染的差异调节，因此通过使用细胞松弛素D处理的巨噬细胞以及新开发的结合高效液相色谱分析的定量逆转录-聚合酶链反应程序，来测定与嗜肺军团菌相互作用的肺泡巨噬细胞（AM）、腹膜常驻巨噬细胞（RM）和腹膜诱导巨噬细胞（EM）中各种细胞因子mRNA的水平，以确定细胞因子mRNA的形成。在体外对嗜肺军团菌附着作出反应的巨噬细胞中，白细胞介素-1β（IL-1β）、IL-6、肿瘤坏死因子α、粒细胞-巨噬细胞集落刺激因子和巨噬细胞炎性蛋白2 mRNA的水平升高。使用该技术，我们表明三种不同的巨噬细胞群体对细菌附着的反应不同。我们发现，嗜肺军团菌附着于AM所诱导的IL-6和粒细胞-巨噬细胞集落刺激因子mRNA水平显著低于RM中的水平，但与EM中的水平相似。此外，发现AM中MIP-2 mRNA的水平高于RM中的水平，但EM中的水平相似。AM和RM中IL-1β mRNA水平均高于EM，但在所检测的三种巨噬细胞群体中肿瘤坏死因子α水平无差异。因此，通过逆转录-聚合酶链反应测定法可轻松定量巨噬细胞对细菌附着产生的细胞因子mRNA水平反应。然而，所得结果显示不同巨噬细胞群体对嗜肺军团菌附着的反应水平不同，这可能与所检测巨噬细胞类型的特性有关。
