M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, Moscow, Russia.
J Virol. 2012 Apr;86(8):4370-9. doi: 10.1128/JVI.06959-11. Epub 2012 Feb 15.
Influenza viruses of gallinaceous poultry and wild aquatic birds usually have distinguishable receptor-binding properties. Here we used a panel of synthetic sialylglycopolymers and solid-phase receptor-binding assays to characterize receptor-binding profiles of about 70 H7 influenza viruses isolated from aquatic birds, land-based poultry, and horses in Eurasia and America. Unlike typical duck influenza viruses with non-H7 hemagglutinin (HA), all avian H7 influenza viruses, irrespective of the host species, displayed a poultry-virus-like binding specificity, i.e., preferential binding to sulfated oligosaccharides Neu5Acα2-3Galβ1-4(6-O-HSO(3))GlcNAc and Neu5Acα2-3Galβ1-4(Fucα1-3)(6-O-HSO(3))GlcNAc. This phenotype correlated with the unique amino acid sequence of the amino acid 185 to 189 loop of H7 HA and seemed to be dependent on ionic interactions between the sulfate group of the receptor and Lys193 and on the lack of sterical clashes between the fucose residue and Gln222. Many North American and Eurasian H7 influenza viruses displayed weak but detectable binding to the human-type receptor moiety Neu5Acα2-6Galβ1-4GlcNAc, highlighting the potential of H7 influenza viruses for avian-to-human transmission. Equine H7 influenza viruses differed from other viruses by preferential binding to the N-glycolyl form of sialic acid. Our data suggest that the receptor-binding site of contemporary H7 influenza viruses in aquatic and terrestrial birds was formed after the introduction of their common precursor from ducks to a new host, presumably, gallinaceous poultry. The uniformity of the receptor-binding profile of H7 influenza viruses in various wild and domestic birds indicates that there is no strong receptor-mediated host range restriction in birds on viruses with this HA subtype. This notion agrees with repeated interspecies transmission of H7 influenza viruses from aquatic birds to poultry.
禽类和野生水禽的流感病毒通常具有可区分的受体结合特性。在这里，我们使用了一组合成的唾液酸糖聚合物和固相受体结合测定法，来描述欧亚大陆和美洲的水禽、陆基家禽和马中约 70 种 H7 流感病毒的受体结合谱。与具有非 H7 血凝素 (HA) 的典型鸭流感病毒不同，所有禽源 H7 流感病毒，无论宿主物种如何，均表现出类似于禽源病毒的结合特异性，即优先结合硫酸化寡糖 Neu5Acα2-3Galβ1-4(6-O-HSO(3))GlcNAc 和 Neu5Acα2-3Galβ1-4(Fucα1-3)(6-O-HSO(3))GlcNAc。这种表型与 H7 HA 氨基酸 185 到 189 环的独特氨基酸序列相关，似乎依赖于受体硫酸根与 Lys193 之间的离子相互作用，以及岩藻糖残基与 Gln222 之间不存在空间冲突。许多北美和欧亚 H7 流感病毒对人源受体部分 Neu5Acα2-6Galβ1-4GlcNAc 表现出微弱但可检测的结合，突出了 H7 流感病毒在禽源向人源传播的潜力。马源 H7 流感病毒与其他病毒的不同之处在于其优先结合 N-乙酰神经氨酸的 N-羟乙酰基形式。我们的数据表明，现代水禽和陆禽中 H7 流感病毒的受体结合位点是在其共同祖先从鸭传播到新宿主（可能是禽类）后形成的。各种野生和家养鸟类中 H7 流感病毒的受体结合谱的一致性表明，在具有这种 HA 亚型的病毒中，鸟类之间没有强烈的受体介导的宿主范围限制。这一观点与 H7 流感病毒从水禽向家禽的反复种间传播一致。
