Endotheliotropism is a hallmark of gallinaceous poultry infections with highly pathogenic avian influenza (HPAI) viruses and a feature that distinguishes HPAI from low pathogenic avian influenza (LPAI) viruses. Here, we used chicken aortic endothelial cells (chAEC) as a novel in vitro infection model to assess the susceptibility, permissiveness, and host response of chicken endothelial cells (EC) to infections with avian influenza (AI) viruses. Our data show that productive replication of AI viruses in chAEC is critically determined by hemagglutinin cleavability, and is thus an exclusive trait of HPAI viruses. However, we provide evidence for a link between limited (i.e. trypsin-dependent) replication of certain LPAI viruses, and the viruses’ ability to dampen the antiviral innate immune response in infected chAEC. Strikingly, this cell response pattern was also detected in HPAI virus-infected chAEC, suggesting that viral innate immune escape might be a prerequisite for robust AI virus replication in chicken EC.

内吞性是高致病性禽流感（HPAI）病毒感染鸡的家禽的标志，并且是将HPAI与低致病性禽流感（LPAI）病毒区分开的特征。在这里，我们使用鸡主动脉内皮细胞（chAEC）作为一种新型的体外感染模型，以评估鸡内皮细胞（EC）对禽流感（AI）病毒感染的敏感性，宽容性和宿主反应。我们的数据表明，chAEC中AI病毒的有效复制是由血凝素的可裂解性决定的，因此是HPAI病毒的专有特征。但是，我们为某些LPAI病毒的有限（即胰蛋白酶依赖性）复制与该病毒减弱受感染chAEC中的抗病毒先天免疫应答的能力之间的联系提供了证据。惊人地