人呼吸道禽流感病毒受体的分布趋势(英文)

Prevalence of Avian Influenza Virus Receptor in Human Respiratory Tract

禽类流感病毒和人类流感病毒具有很强的受体识别特异性,分别与唾液酸α-2,3Gal和α-2,6Gal受体分子结合而感染各自的宿主细胞.这种受体结合特异性是流感病毒在禽类和人类之间跨种属传递的主要障碍.应用凝集素组织化学染色技术,探讨人呼吸道各解剖学部位流感病毒唾液酸受体的分布特征.结果显示,唾液酸α-2,3Gal受体,即禽类流感受体,主要分布在下呼吸道的呼吸部即呼吸细支气管和肺泡,而在主气管、支气管和细支气管仅少量分布.相反,人类流感病毒受体,唾液酸α-2,6Gal受体在气管、支气管呈高密度分布,随着支气管分级逐渐降低分布减少,至肺泡分布最少.但比较人呼吸道发育成熟过程中,唾液酸α-2,3Gal和α-2,6Gal受体的表达,未发现明显差别.禽流感H5N1病毒体外感染人呼吸道组织试验结果表明,肺泡上皮较支气管和气管上皮易感染,与唾液酸α-2,3Gal受体分布特点相符合.结果提示,人呼吸道可被禽流感病毒感染,目前H5N1病毒极少发生人传人的特点,可能与个体间上呼吸道唾液酸α-2,3Gal受体表达差异有关.

SAα2,6 and SAα2,3 linked sialic acid molecules on epithelial cell membrane served as receptors for influenza virus, which are specifically recognized by human and avian influenza viruses, respectively. The distribution of these two species of sialic acids in human respiratory tract from different anatomical sites and different age groups was investigated. The results showed that SAα2,3Gal species was prevalent in respiratory bronchiole and lung alveolar epithelium, but was infrequent in trachea, bronchus and bronchiole. On the contrary, the SAα2,6Gal species was more common in the trachea and bronchus and to a lesser degree in the alveolar epithelium. When compared the expression levels of SAα2,6Gal and α2,3Gal in the respiratory tract among different age groups, no significant difference was found. In the ex vivo H5N1 virus infection study, alveolus epithelium were found to be more susceptible to avian influenza than trachea and bronchus epithelial cells. These results suggest that the human respiratory tract, to some extent, is permissive for avian influenza viruses. The currently-observed limited human to human transmission of H5N1 virus may be associated with the different abundance of SAα2,3Gal linkages in human upper respiratory tract among individuals.