Nature ：流感病毒的气溶胶传播

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人类流感病毒优先使用含 “a2,6-linked 唾液酸(SA)”的受体，而禽流感病毒则优先结合 “a2,3-linked SA”。

流感病毒在人与人之间的高效空气传播与a2,6-linked SA、而不是a2,3-linked SA的使用有关。采用一个“功能丧失”(loss-of-function)方法(在其中，一个在2009年造成疫情的H1N1流感病毒被人为地与a2,3-SA相结合)，Kanta Subbarao及同事通过雪貂显示，软腭是发生受体使用之切换的一个重要场所，该组织会迅速选择对人类受体有偏好的可传播的流感病毒。

这项工作连同以前发表的数据表明，在评估甲流病毒造成流感疫情的潜力时，也许应该分析它们在软腭中的复制适应性。

来源：生物360

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The soft palate is an important site of adaptation for transmissible influenza viruses

Seema S. Lakdawala,        Akila Jayaraman,        Rebecca A. Halpin,        Elaine W. Lamirande,        Angela R. Shih,        Timothy B. Stockwell,        Xudong Lin,        Ari Simenauer,        Christopher T. Hanson,        Leatrice Vogel,        Myeisha Paskel,        Mahnaz Minai,        Ian Moore,        Marlene Orandle,        Suman R. Das,        David E. Wentworth,        Ram Sasisekharan        & Kanta Subbarao

Influenza A viruses pose a major public health threat by causing seasonal epidemics and sporadic pandemics. Their epidemiological success relies on airborne transmission from person to person; however, the viral properties governing airborne transmission of influenza A viruses are complex. Influenza A virus infection is mediated via binding of the viral haemagglutinin (HA) to terminally attached α2,3 or α2,6 sialic acids on cell surface glycoproteins. Human influenza A viruses preferentially bind α2,6-linked sialic acids whereas avian influenza A viruses bind α2,3-linked sialic acids on complex glycans on airway epithelial cells1, 2. Historically, influenza A viruses with preferential association with α2,3-linked sialic acids have not been transmitted efficiently by the airborne route in ferrets3, 4. Here we observe efficient airborne transmission of a 2009 pandemic H1N1 (H1N1pdm) virus (A/California/07/2009) engineered to preferentially bind α2,3-linked sialic acids. Airborne transmission was associated with rapid selection of virus with a change at a single HA site that conferred binding to long-chain α2,6-linked sialic acids, without loss of α2,3-linked sialic acid binding. The transmissible virus emerged in experimentally infected ferrets within 24 hours after infection and was remarkably enriched in the soft palate, where long-chain α2,6-linked sialic acids predominate on the nasopharyngeal surface. Notably, presence of long-chain α2,6-linked sialic acids is conserved in ferret, pig and human soft palate. Using a loss-of-function approach with this one virus, we demonstrate that the ferret soft palate, a tissue not normally sampled in animal models of influenza, rapidly selects for transmissible influenza A viruses with human receptor (α2,6-linked sialic acids) preference.

http://www.nature.com/nature/jou ... ll/nature15379.html