Demuth A, Goebel W, Beuscher H U, Kuhn M
Lehrstuhl für Mikrobiologie, Theodor-Boveri-Institut für Biowissenschaften, Universität Würzburg, Germany.
Infect Immun. 1996 Sep;64(9):3475-83. doi: 10.1128/iai.64.9.3475-3483.1996.
Cytokine and cytokine receptor mRNA expression was analyzed by PCR-assisted amplification of RNA extracted from bone marrow-derived macrophages (BMM phi) at different time points after infection with Listeria monocytogenes. The mRNAs for the cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, and tumor necrosis factor alpha (TNF-alpha) were induced early after infection, whereas IL-6 mRNA appeared later and even nonhemolytic Listeria strains, which are unable to grow inside eukaryotic cells, induced the same cytokine mRNAs at levels similar to those of the wild-type strain. In most cases, the amounts of cytokines determined by various bioassays correlated with the level of mRNA induction. Inhibition of phagocytic uptake of L. monocytogenes by cytochalasin D treatment resulted in adherent bacteria which still induced the proinflammatory cytokines. In BMM phi, the level of IL-1 receptor II mRNA was unaffected, whereas mRNA expression of the two subtypes of tumor necrosis factor receptors (TNF-RI and TNF-RII) was differentially regulated upon infection: transcription of TNF-RI was reduced, and that of TNF-RII mRNA was induced. Similar to the decreased TNF-RI mRNA expression, gamma interferon receptor mRNA was downregulated in L. monocytogenes-infected BMM phi. This dose- and time-dependent induction or downregulation of cytokine receptor mRNA following L. monocytogenes infection of BMM phi was not observed upon infection of established macrophage-like cell lines J774 and P388D1. Induction of IL-6 mRNA as well as IL-1 alpha/beta and TNF-alpha mRNAs upon L. monocytogenes infection of BMM phi occurs independently of autocrine TNF-alpha signaling via TNF-RI or TNF-RII, as shown by infection of TNF-RI- and TNF-RII-deficient macrophages derived from mutant B6 x 129 mice. In contrast to gamma interferon receptor mRNA, both TNF receptor subtype mRNAs were not influenced by L. monocytogenes infection of hybrid (B6 x 129) mouse macrophages. Whereas the proinflammatory cytokine mRNAs were even induced after infection with the nonpathogenic species L. innocua, no alteration of cytokine receptor mRNA expression was observed after challenge of BMM phi with this nonpathogenic species, suggesting that the modulation of cytokine and cytokine receptor expression by L. monocytogenes could be an important way of inhibition of macrophage stimulation.
通过PCR辅助扩增从单核细胞增生李斯特菌感染后不同时间点的骨髓来源巨噬细胞（BMM phi）中提取的RNA，分析细胞因子和细胞因子受体mRNA的表达。细胞因子白细胞介素-1α（IL-1α）、IL-1β和肿瘤坏死因子α（TNF-α）的mRNA在感染后早期被诱导，而IL-6 mRNA出现较晚，甚至不能在真核细胞内生长的非溶血性李斯特菌菌株，也能以与野生型菌株相似的水平诱导相同的细胞因子mRNA。在大多数情况下，通过各种生物测定法测定的细胞因子量与mRNA诱导水平相关。用细胞松弛素D处理抑制单核细胞增生李斯特菌的吞噬摄取，导致仍能诱导促炎细胞因子的黏附细菌。在BMM phi中，IL-1受体II mRNA的水平未受影响，而肿瘤坏死因子受体的两种亚型（TNF-RI和TNF-RII）的mRNA表达在感染后受到不同调节：TNF-RI的转录减少，而TNF-RII mRNA的转录被诱导。与TNF-RI mRNA表达降低类似，γ干扰素受体mRNA在单核细胞增生李斯特菌感染的BMM phi中也被下调。在用单核细胞增生李斯特菌感染BMM phi后，这种剂量和时间依赖性的细胞因子受体mRNA诱导或下调在已建立的巨噬细胞样细胞系J774和P388D1感染时未观察到。如来自突变B6×129小鼠的TNF-RI和TNF-RII缺陷巨噬细胞感染所示，单核细胞增生李斯特菌感染BMM phi后IL-6 mRNA以及IL-1α/β和TNF-α mRNA的诱导独立于通过TNF-RI或TNF-RII的自分泌TNF-α信号传导。与γ干扰素受体mRNA不同，两种TNF受体亚型mRNA均不受杂交（B6×129）小鼠巨噬细胞单核细胞增生李斯特菌感染的影响。虽然用无毒种无害李斯特菌感染后促炎细胞因子mRNA甚至被诱导，但用这种无毒种攻击BMM phi后未观察到细胞因子受体mRNA表达的改变，这表明单核细胞增生李斯特菌对细胞因子和细胞因子受体表达的调节可能是抑制巨噬细胞刺激的一种重要方式。
