Table_2_Immune-Related Gene Expression in Ducks Infected With Waterfowl-Origin H5N6 Highly Pathogenic Avian Influenza Viruses.docx

Clade 2.3.4.4 H5 avian influenza viruses (AIVs) are widely prevalent and of significant concern to the poultry industry and public health in China. Nowadays, the clade 2.3.4.4 H5N6 virus has become a dominant AIV subtype among domestic ducks in southern China. We found that waterfowl-origin clade 2.3.4.4 H5N6 viruses (A/goose/Guangdong/16568/2016, GS16568 and A/duck/Guangdong/16873/2016, DK16873) isolated from southern China in 2016 could replicate in multiple organs of inoculated ducks. DK16873 virus caused mild infections and killed 2/5 of inoculated ducks, and GS16568 virus did not kill inoculated ducks. In addition, the two viruses could be transmitted via direct contact between ducks. DK16873 and GS16568 viruses killed 2/5 and 1/5 of contact ducks, respectively. Furthermore, ducks inoculated with the two H5N6 viruses exhibited different expressions of immune-related genes in their lungs. The expression of RIG-I, TLR3 and IL6 was significantly upregulated at 12 h post-inoculation (HPI) and most of the tested immune-related genes were significantly upregulated at 3 days post-inoculation (DPI). Notably, the expression of RIG-I and IL-6 in response to DK16873 virus was significantly higher than for GS16568 virus at 12 HPI and 3 DPI. Our research have provided helpful information about the pathogenicity, transmission and immune-related genes expression in ducks infected with new H5N6 AIVs.

进化分支2.3.4.4亚型H5禽流感病毒（avian influenza viruses，以下简称AIVs）在中国广泛流行，备受家禽养殖业与公共卫生领域高度关注。目前，进化分支2.3.4.4的H5N6亚型病毒已成为中国南方家鸭群体中占主导地位的禽流感病毒亚型。本研究发现，2016年从中国南方分离得到的水禽源进化分支2.3.4.4 H5N6禽流感病毒（A/goose/Guangdong/16568/2016，简称GS16568；A/duck/Guangdong/16873/2016，简称DK16873）可在接种家鸭的多个脏器中增殖。DK16873毒株可引发轻度感染，导致5只接种鸭中的2只死亡；而GS16568毒株未造成接种鸭死亡。此外，这两种病毒均可通过家鸭间的直接接触传播：DK16873与GS16568毒株分别导致5只接触感染鸭中的2只和1只死亡。进一步研究发现，接种这两种H5N6毒株的家鸭，其肺部免疫相关基因的表达模式存在显著差异。在接种后12小时（12 HPI），RIG-I、TLR3及IL6的表达量显著上调；在接种后3天（3 DPI），大部分检测的免疫相关基因表达量均显著上调。值得注意的是，在12 HPI与3 DPI时，DK16873毒株诱导的RIG-I与IL-6表达水平显著高于GS16568毒株。本研究为新型H5N6禽流感病毒感染家鸭后的致病性、传播特性以及免疫相关基因表达特征提供了有价值的参考依据。