Guo Chao-Tan, Takahashi Noriko, Yagi Hirokazu, Kato Koichi, Takahashi Tadanobu, Yi Shuang-Qin, Chen Yong, Ito Toshihiro, Otsuki Koichi, Kida Hiroshi, Kawaoka Yoshihiro, Hidari Kazuya I-P Jwa, Miyamoto Daisei, Suzuki Takashi, Suzuki Yasuo
Institute of Bioengineering, Zhejiang Academy of Medical Sciences, 182 Tianmushan Road, Hangzhou 310016, China.
Glycobiology. 2007 Jul;17(7):713-24. doi: 10.1093/glycob/cwm038. Epub 2007 Mar 27.
The receptor specificity of influenza viruses is one factor that allows avian influenza viruses to cross the species barrier. The recent transmissions of avian H5N1 and H9N2 influenza viruses from chickens and/or quails to humans indicate that avian influenza viruses can directly infect humans without an intermediate host, such as pigs. In this study, we used two strains of influenza A virus (A/PR/8/34, which preferentially binds to an avian-type receptor, and A/Memphis/1/71, which preferentially binds to a human-type receptor) to probe the receptor specificities in host cells. Epithelial cells of both quail and chicken intestines (colons) could bind both avian- and human-type viruses. Infected cultured quail colon cells expressed viral protein and allowed replication of the virus strain A/PR/8/34 or A/Memphis/1/71. To understand the molecular basis of these phenomena, we further investigated the abundance of sialic acid (Sia) linked to galactose (Gal) by the alpha2-3 linkage (Siaalpha2-3Gal) and Siaalpha2-6Gal in host cells. In glycoprotein and glycolipid fractions from quail and chicken colon epithelial cells, there were some bound components of Sia-Gal linkage-specific lectins, Maackia amurensis agglutinin (specific for Siaalpha2-3 Gal) and Sambucus nigra agglutinin (specific for Siaalpha2-6Gal), indicating that both Siaalpha2-3Gal and Siaalpha2-6Gal exist in quail and chicken colon cells. Furthermore, we demonstrated by fluorescence high-performance liquid chromatography (HPLC) analysis that 5-N-acetylneuraminic acid was the main molecular species of Sia, and we demonstrated by multi-dimensional HPLC mapping and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis that bi-antennary complex-type glycans alpha2-6 sialylated at the terminal Gal residue(s) are major (more than 79%) sialyl N-glycans expressed by intestinal epithelial tissues in both the chicken and quail. Taken together, these results indicate that quails and chickens have molecular characterization as potential intermediate hosts for avian influenza virus transmission to humans and could generate new influenza viruses with pandemic potential.
流感病毒的受体特异性是禽流感病毒跨越物种屏障的一个因素。最近，H5N1和H9N2禽流感病毒从鸡和/或鹌鹑直接传播给人类，这表明禽流感病毒可以在没有猪等中间宿主的情况下直接感染人类。在本研究中，我们使用了两株甲型流感病毒（A/PR/8/34，优先结合禽源型受体；A/Memphis/1/71，优先结合人源型受体）来探究宿主细胞中的受体特异性。鹌鹑和鸡肠道（结肠）的上皮细胞均可结合禽源型和人源型病毒。感染的培养鹌鹑结肠细胞表达病毒蛋白，并允许A/PR/8/34或A/Memphis/1/71病毒株复制。为了解这些现象的分子基础，我们进一步研究了宿主细胞中通过α2-3连接（唾液酸α2-3半乳糖）和唾液酸α2-6半乳糖与半乳糖（Gal）相连的唾液酸（Sia）的丰度。在鹌鹑和鸡结肠上皮细胞的糖蛋白和糖脂组分中，存在一些唾液酸-半乳糖连接特异性凝集素（马尿泡凝集素，对唾液酸α2-3半乳糖具有特异性；黑接骨木凝集素，对唾液酸α2-6半乳糖具有特异性）的结合成分，这表明唾液酸α2-3半乳糖和唾液酸α2-6半乳糖均存在于鹌鹑和鸡的结肠细胞中。此外，我们通过荧光高效液相色谱（HPLC）分析证明，5-N-乙酰神经氨酸是唾液酸的主要分子种类，并且通过多维HPLC图谱分析和基质辅助激光解吸/电离飞行时间质谱分析证明，在末端半乳糖残基上α2-6唾液酸化的双天线复合型聚糖是鸡和鹌鹑肠道上皮组织表达的主要（超过79%）唾液酸化N-聚糖。综上所述，这些结果表明，鹌鹑和鸡具有作为禽流感病毒传播给人类的潜在中间宿主的分子特征，并且可能产生具有大流行潜力的新型流感病毒。
