In 2014, an outbreak of avian A/H10N7 influenza virus occurred among seals along North-European coastal waters, significantly impacting seal populations. Here, we examine the cross-species transmission and mammalian adaptation of this influenza A virus, revealing changes in the hemagglutinin surface protein that increase stability and receptor binding. The seal A/H10N7 virus was aerosol or respiratory droplet transmissible between ferrets. Compared with avian H10 hemagglutinin, seal H10 hemagglutinin showed stronger binding to the human-type sialic acid receptor, with preferential binding to α2,6-linked sialic acids on long extended branches. In X-ray structures, changes in the 220-loop of the receptor-binding pocket caused similar interactions with human receptor as seen for pandemic strains. Two substitutions made seal H10 hemagglutinin more stable than avian H10 hemagglutinin and similar to human hemagglutinin. Consequently, identification of avian-origin influenza viruses across mammals appears critical to detect influenza A viruses posing a major threat to humans and other mammals.

2014 年，在北欧沿海水域的海豹中爆发了禽 A/H10N7 流感病毒，对海豹种群产生了重大影响。在这里，我们检查了这种甲型流感病毒的跨物种传播和哺乳动物适应，揭示了血凝素表面蛋白的变化，这些变化增加了稳定性和受体结合。海豹 A/H10N7 病毒是可在雪貂之间传播的气溶胶或呼吸道飞沫。与禽类 H10 血凝素相比，海豹 H10 血凝素与人型唾液酸受体的结合更强，优先结合长分支上的 α2,6 连接的唾液酸。在 X 射线结构中，受体结合口袋的 220 环的变化引起了与人类受体类似的相互作用，如大流行毒株所见。两个替换使海豹 H10 血凝素比禽类 H10 血凝素更稳定，并且与人类血凝素相似。因此，鉴定跨哺乳动物的禽源流感病毒对于检测对人类和其他哺乳动物构成重大威胁的甲型流感病毒至关重要。