Yang Hua, Carney Paul J, Chang Jessie C, Guo Zhu, Villanueva Julie M, Stevens James
Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Virology. 2015 Mar;477:18-31. doi: 10.1016/j.virol.2014.12.024. Epub 2015 Jan 22.
A(H3N2) influenza viruses have circulated in humans since 1968, and antigenic drift of the hemagglutinin (HA) protein continues to be a driving force that allows the virus to escape the human immune response. Since the major antigenic sites of the HA overlap into the receptor binding site (RBS) of the molecule, the virus constantly struggles to effectively adapt to host immune responses, without compromising its functionality. Here, we have structurally assessed the evolution of the A(H3N2) virus HA RBS, using an established recombinant expression system. Glycan binding specificities of nineteen A(H3N2) influenza virus HAs, each a component of the seasonal influenza vaccine between 1968 and 2012, were analyzed. Results suggest that while its receptor-binding site has evolved from one that can bind a broad range of human receptor analogs to one with a more restricted binding profile for longer glycans, the virus continues to circulate and transmit efficiently among humans.
自1968年以来，A(H3N2)流感病毒一直在人类中传播，血凝素（HA）蛋白的抗原漂移仍然是促使该病毒逃避人类免疫反应的一个驱动力。由于HA的主要抗原位点重叠于该分子的受体结合位点（RBS），病毒不断努力在不损害其功能的情况下有效适应宿主免疫反应。在此，我们使用一个成熟的重组表达系统，从结构上评估了A(H3N2)病毒HA RBS的进化情况。分析了1968年至2012年间作为季节性流感疫苗成分的19种A(H3N2)流感病毒HA的聚糖结合特异性。结果表明，虽然其受体结合位点已从一个能结合广泛人类受体类似物的位点演变为一个对更长聚糖结合谱更受限的位点，但该病毒仍在人类中持续高效传播。
