不同毒力和剂量的新城疫病毒感染鸡胚后固有免疫相关分子mRNA转录水平的变化

Transcriptional Responses of Innate Immunity Related mRNAs after Infection of Embryonated Chicken Eggs with Newcastle Disease Viruses of Variant Virulence and Doses

新城疫是由新城疫病毒引起的一种重要的禽类传染病,给全球养禽业造成严重的经济损失。为更好地了解固有免疫应答在新城疫病毒致病机制中所起的作用,笔者分别以不同剂量的基因VII型新城疫病毒强毒株和LaSota弱毒株感染SPF鸡胚,使用荧光定量PCR方法检测和分析感染早期的病毒增殖和固有免疫相关分子转录水平的动态变化。结果表明,强、弱毒株均可有效地激活鸡胚固有免疫信号通路,导致包括细胞模式识别受体、干扰素、白细胞介素和抗病毒蛋白等基因转录水平的变化。同一病毒以高剂量感染,较之低剂量感染后的增殖速度快,固有免疫相关基因表达上调的峰值出现得也较早。强毒株相比弱毒株诱导鸡体产生了更高水平的干扰素和白细胞介素,与强毒感染导致鸡体严重的临床症状和病理损伤相一致。总之,本研究发现,新城疫病毒感染后鸡胚固有免疫应答的速度和水平因病毒毒力和感染剂量的不同而异。基因VII型新城疫病毒可诱导强烈的细胞固有免疫炎性反应,可能是它对鸡致病性高的重要原因。

Newcastle disease virus（NDV）is the pathogen of Newcastle disease（ND）,which causes serious economic losses to poultry industry.For a better understanding of innate immune response in the pathogenesis of NDVs,SPF chicken embryos were infected with a virulent NDV strain and an avirulent vaccine strain-LaSota,respectively,with different infection doses set for both viruses.At the early stage of viral infection,the dynamics of viral proliferation and the transcriptional level of innate immune-related molecules were tested with fluorescence quantitative PCR assays.The results showed that both the virulent and avirulent NDV strains could activate the innate immune signaling pathways,and resulted in the transcriptional changes of cellular pat-tern recognition receptors,interferons,interleukins and antiviral proteins.NDV infection of high doses in comparison with low doses resulted in quicker viral proliferation and earlier peaks of innate immune-related gene expression.The virulent NDV strain induced higher levels of interferons and inflammatory cytokines in chicken embryos,which was consistent with the severe inflammation and pathological damages of both chicken embryos and chickens caused by virulent viral infection.In conclusion,this study found that the response patterns of chicken innate immune signaling pathways varied due to NDV virulence and infection dose,and the genotype VII NDV strain could induce strong cellular inflammatory responses,which may contribute to its high pathogenicity to chickens.