Virus Laboratory, the Affiliated Shengjing Hospital, China Medical University, Shenyang, Liaoning, People's Republic of China.
Virol J. 2013 Feb 12;10:51. doi: 10.1186/1743-422X-10-51.
Interleukin-32 (IL-32) is an important factor in innate and adaptive immune responses, which activates the p38MAPK, NF-kappa B and AP-1 signaling pathways. Recent reports have highlighted that IL-32 is regulated during viral infection in humans.
Enzyme-linked immunosorbent assays (ELISA) were carried out to detect IL-32 levels in serum samples. Detailed kinetics of the transcription of IL-32 mRNA and expression of IL-32 protein during human cytomegalovirus (HCMV) infection were determined by semi-quantitative RT-PCR and western blot, respectively. The expression levels of hcmv-miR-UL112-1 were detected using TaqMan® miRNA assays during a time course of 96 hours. The effects of hcmv-miR-UL112-1 on IL-32 expression were demonstrated by luciferase assay and western blot, respectively.
Serum levels of IL-32 in HCMV-IgM positive patients (indicating an active HCMV infection) were significantly higher than those in HCMV-IgM negative controls. HCMV infection activated cellular IL-32 transcription mainly in the immediately early (IE) phase and elevated IL-32 protein levels between 6 and 72 hours post infection (hpi) in the human embryonic lung fibroblast cell line, MRC-5. The expression of hcmv-miR-UL112-1 was detected at 24 hpi and increased gradually as the HCMV-infection process was prolonged. In addition, it was demonstrated that hcmv-miR-UL112-1 targets a sequence in the IL-32 3'-UTR. The protein level of IL-32 in HEK293 cells could be functionally down-regulated by transfected hcmv-miR-UL112-1.
IL-32 expression was induced by active HCMV infection and could be functionally down-regulated by ectopically expressed hcmv-miR-UL112-1. Our data may indicate a new strategy of immune evasion by HCMV through post-transcriptional regulation.
白细胞介素 32（IL-32）是固有和适应性免疫反应中的一个重要因素，它激活了 p38MAPK、NF-κB 和 AP-1 信号通路。最近的报告强调，IL-32 在人类病毒感染过程中受到调控。
通过酶联免疫吸附试验（ELISA）检测血清样本中的 IL-32 水平。通过半定量 RT-PCR 和 Western blot 分别确定人巨细胞病毒（HCMV）感染过程中 IL-32 mRNA 的转录和 IL-32 蛋白的表达的详细动力学。在 96 小时的时间过程中，使用 TaqMan®miRNA 测定法检测 hcmv-miR-UL112-1 的表达水平。通过荧光素酶测定和 Western blot 分别证明 hcmv-miR-UL112-1 对 IL-32 表达的影响。
HCMV-IgM 阳性患者（表明存在活动性 HCMV 感染）的血清 IL-32 水平明显高于 HCMV-IgM 阴性对照组。HCMV 感染主要在即刻早期（IE）阶段激活细胞内 IL-32 转录，并在感染后 6 至 72 小时（hpi）升高人胚肺成纤维细胞系 MRC-5 中的 IL-32 蛋白水平。在 24 hpi 时检测到 hcmv-miR-UL112-1 的表达，并随着 HCMV 感染过程的延长而逐渐增加。此外，证明 hcmv-miR-UL112-1 靶向 IL-32 3'-UTR 的一个序列。转染 hcmv-miR-UL112-1 可使 HEK293 细胞中 IL-32 的蛋白水平功能下调。
IL-32 的表达受活性 HCMV 感染诱导，并可被异位表达的 hcmv-miR-UL112-1 功能下调。我们的数据可能表明 HCMV 通过转录后调控来实现免疫逃避的新策略。
