呼吸道合胞病毒感染人肺上皮细胞活化Toll样受体3介导的抗病毒作用研究

目的 探讨呼吸道合胞病毒( RSV)感染人肺上皮A549细胞后,Toll样受体3(TLR3)的水平变化及其产生的Ⅰ型干扰素的抗病毒作用.方法 RSV感染体外培养的人肺上皮A549细胞,并给予TLR3特异性抗体处理,分别感染4、8、12、16、24h后收集各组细胞.未感染病毒的细胞作为对照组.RT-PCR法检测TLR3、IFN-α、IFN-β,RSV F蛋白的mRNA表达水平变化.结果 RSV感染A549细胞后,TLR3、IFN-α、IFN-β,RSV F蛋白的mRNA表达量均升高且有时间依赖性,TLR3 mRNA在24h表达量是基础表达量的5倍,IFN-α、IFN-β mRNA在24 h表达量是基础表达量的4倍多,RSVF蛋白的mRNA表达量近1.7倍.TLR3抗体预先处理以抑制TLR3受体,再行RSV感染,IFN-α和IFN-β mRNA表达量虽然升高,但较感染组均有所下降,mRNA表达在12 h后显著降低,且IFN-ββ的mRNA表达量下调更明显.但RSV F基因的mRNA表达在12 h、24 h升高有显著性差异.结论 RSV感染A549细胞后可上调TLR3表达,其活化细胞介导产生的Ⅰ型干扰素起抗病毒作用,在一定程度上可抑制病毒的增殖水平.

The antiviral role of Toll-like receptor 3 in human lung epithelial cells infected with respiratory syncytial virus

Objective In order to understand the production mechanism of interferon and provide a scientific basis for preventionand clinical therapy, the expression changes of Toll-like receptor （ TLR3 ） mRNA and the role of TLR3 in human lung epithelial ceils （ A549 cells） infected with respiratory syncytial virus （RSV） were investigated in this study. Methods RSV infected A549 cells were treated with or without specific antibodies of TLR3 and collected at the selected timepoints after RSV infection （4,8,12,16 and 24h）. The expressions of TLR3 ,IFN-α,IFN-β and RSV F mRNA were evaluated by RT-PCR. Result It was found that RSV infection could markedly up-regulate the mRNA expression of TLR3, IFN-α, IFN-β and RSV F protein in a time-dependent manner as the 24h mRNA expressions of them were 4 times,3 times, 3 times and 0.7 times mot than the basic expression, respectively. Treatment of TLR3 specific antibodies, whereas,significantly down-regulated the activation of TLR3. The mRNA expression of IFN-α and IFN-β also decreased accordingly and that of IFN-β reduced more obviously than IFN-α,but that of RSV F protein rose significantly. Conclusion Above data indicate that RSV infection could induce an apparent increase of antiviral genes of IFN-α and IFN-β by activating TLR3 in human lung epithelial cells and the activated cells mediated Type I interferon is antiviral,which suggesting that TLR3 might play an important role in antiviral activity of RSV-infected human lung epithelial cells.