与H5亚型禽流感病毒结合人源唾液酸受体相关的关键氨基酸位点的筛选

Since the first human infected H5 subtype avian influenza virus (AIV) in 1997, a total of 879 cases of human infection with H5 subtype AIVs have been reported. These cases were sporadic, without causing influenza pandemic. It was commonly accepted that binding to human-type sialic acids receptors is a prerequisite for an avian influenza virus to transmit among humans. Recent surveillance data indicated that some H5 subtype AIV acquired the ability to bind human-type sialic acid receptors, and some H5 subtype AIV could transmit efficiently by direct contact in ferrets or guinea pigs, posing the threat to cause a pandemic. In order to clarify the basis of H5 subtype AIV binding to human-type sialic acid receptors, we using the classical reverse genetic operation plate and solid-phase binding ELISA assay of AIV to screen the key amino acid sites that affect H5 subtype AIV binding human-type sialic acid receptors, and then analysis the distribution and the universal role of the key amino acid sites in H5 subtype AIV. Subsequently, we evaluate the transmission risk in mammals of H5 subtype AIV with the key amino acid sites using guinea pigs as the animal model. Therefore, this project has very important public health significance and has great guiding significance to the surveillance and evaluating the cross-species transmission risk of AIV.

自1997年H5亚型禽流感病毒（AIV）首次感染人类以来，全球已有879人感染，目前该病在人群中主要表现为散发，尚未引起流感大流行。获得结合人源唾液酸受体能力是AIV在人群中传播的先决条件，近期监测数据显示部分H5亚型AIV获得了结合人源唾液酸受体的能力，有些病毒还可以在哺乳动物模型豚鼠或雪貂间高效接触传播，具有引起流感大流行的潜在威胁。为了揭示H5亚型AIV获得结合人源唾液酸受体能力的本质，本研究利用AIV经典的反向遗传操作平台和固相结合ELISA实验，筛选影响H5亚型AIV结合人源唾液酸受体的关键氨基酸位点，并分析该位点在H5亚型AIV间的分布情况和发挥作用的普遍性。然后，以豚鼠为动物模型评价具有关键氨基酸位点的H5亚型AIV在哺乳动物间的传播风险，能够为禽流感的监测预警和跨物种传播风险评估提供科学依据，具有十分重要的公共卫生学意义。

H5亚型禽流感病毒不仅可以感染野鸟和家禽，同时还可以跨越种间屏障直接感染人类，对人类生命健康构成严重威胁。获得结合人源唾液酸受体能力是禽流感病毒跨越种间屏障感染人类的先决条件，本研究利用固相结合ELISA实验，对近年来分离的H5亚型禽流感病毒的受体结合特异性进行了系统分析，结果表明部分H5亚型禽流感病毒获得了结合人源唾液酸受体能力，利用流感病毒反向遗传操作平台，成功筛选到HA蛋白的130、155和193位点处的氨基酸残基是影响H5亚型禽流感病毒结合人源唾液酸受体的关键氨基酸位点，并且这3个氨基酸位点发挥作用具有良好的普遍性。传播实验结果表明，部分具有增强H5亚型禽流感病毒结合人源唾液酸受体结合能力关键氨基酸位点特征的毒株，能够在豚鼠间进行直接接触传播，具有在人群中传播的潜在风险。本研究的顺利开展为禽流感监测预警和综合防控提供了科学依据，具有十分重要的公共卫生学意义。