Table_1_Chickens Expressing IFIT5 Ameliorate Clinical Outcome and Pathology of Highly Pathogenic Avian Influenza and Velogenic Newcastle Disease Viruses.DOCX

Innate antiviral immunity establishes first line of defense against invading pathogens through sensing their molecular structures such as viral RNA. This antiviral potential of innate immunity is mainly attributed to a myriad of IFN-stimulated genes (ISGs). Amongst well-characterized ISGs, we have previously shown that antiviral potential of chicken IFN-induced proteins with tetratricopeptides repeats 5 (chIFIT5) is determined by its interaction potential with 5′ppp containing viral RNA. Here, we generated transgenic chickens using avian sarcoma-leukosis virus (RCAS)-based gene transfer system that constitutively and stably express chIFIT5. The transgenic chickens infected with clinical dose (EID50 104 for HPAIV and 105 EID50 for vNDV) of high pathogenicity avian influenza virus (HPAIV; H5N1) or velogenic strain of Newcastle disease virus (vNDV; Genotype VII) showed marked resistance against infections. While transgenic chickens failed to sustain a lethal dose of these viruses (EID50 105 for HPAIV and 106 EID50 for vNDV), a delayed and lower level of clinical disease and mortality, reduced virus shedding and tissue damage was observed compared to non-transgenic control chickens. These observations suggest that stable expression of chIFIT5 alone is potentially insufficient in providing sterile protection against these highly virulent viruses; however, it is sufficient to ameliorate the clinical outcome of these RNA viruses. These findings propose the potential of innate immune genes in conferring genetic resistance in chickens against highly pathogenic and zoonotic viral pathogens causing sever disease in both animals and humans.

天然抗病毒免疫通过识别入侵病原体的分子结构（如病毒RNA），构建抵御病原体的第一道防线。该天然免疫的抗病毒潜力主要来源于大量干扰素刺激基因（IFN-stimulated genes，ISGs）。在已被充分表征的ISGs中，我们前期研究证实，鸡源含四肽重复序列的干扰素诱导蛋白5（chIFIT5）的抗病毒活性，取决于其与携带5′ppp的病毒RNA的结合能力。本研究借助基于禽肉瘤白血病病毒（RCAS）的基因转移系统，构建了组成型稳定表达chIFIT5的转基因鸡。当以临床感染剂量（高致病性禽流感病毒HPAIV为10^4 鸡胚半数感染量（EID50），新城疫病毒vNDV为10^5 EID50）接种高致病性禽流感病毒（HPAIV；H5N1亚型）或新城疫病毒强毒株（vNDV；基因型VII型）时，转基因鸡表现出显著的感染抗性。尽管转基因鸡无法抵御上述病毒的致死剂量攻击（HPAIV为10^5 EID50，vNDV为10^6 EID50），但与非转基因对照鸡相比，其临床病症与死亡率均出现延迟且程度更低，病毒排毒量减少，组织损伤也有所减轻。上述结果表明，仅稳定表达chIFIT5或许不足以实现对这些高毒力病毒的完全无菌保护，但足以改善这类RNA病毒感染后的临床转归。本研究结果提示，天然免疫基因在赋予鸡只遗传抗性方面具备潜力，可帮助鸡只抵御那些可在动物与人类中引发严重疾病的高致病性、人畜共患病毒病原体。