在24株AIV分离株中,A/Mallard/South Korea/KNU2019-34/2019(KNU19-34; H1N1)导致小鼠出现显著体重下降及高致死率。该病毒可在肺、肾、心脏中高效复制。值得注意的是,感染KNU19-34的雪貂鼻腔冲洗液与肺组织均检测到高病毒载量。该毒株在A549细胞中复制效率与2009年大流行毒株A/California/04/2009 (H1N1) 相似,且优先结合人类受体α2,6-唾液酸(而非禽类受体α2,3-唾液酸)。遗传进化分析显示,KNU19-34的基因片段分布于2015-2018年埃及与亚洲谱系,且相较于对小鼠无致病性的H1N1禽流感毒株存在多个关键氨基酸替换。综合证据表明,KNU19-34具备人畜共患病传播潜能,且可能通过新发突变进一步适应哺乳动物宿主。
Fig. 1. KNU19-34 (H1N1) infection in mice results in severe pathogenic effects.
Fig. 2. KNU19-34 causes high viral titers in lungs, kidney, and heart in mice.
Fig. 3. KNU19-34 infection exhibits high viral loads in both nasal washes and lung in ferrets.
Fig. 4. Rapid growth kinetics of the KNU19-34 (H1N1) in A549 cells.
Fig. 5. The KNU19-34 (H1N1) isolate shows high binding specificity for α2,6-linked sialic acid receptors.
Fig. 6. Putative origins of the genomic components identified in the KNU19-34 (H1N1) strain.Table 1. Survival rate and weight loss in mice infected with AIV isolates.
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Table 2. Viral titers and infection ratio in various tissues of mice infected with KNU19-34.
Table 3. Mutational analysis of eight genes among the H1N1 isolates used in this study.