1918年爆發(fā)流感大流行,，在數(shù)個月內(nèi)造成全球大約5000萬人死亡,，而今,，科學(xué)家們發(fā)現(xiàn),，若改變病毒體的外殼蛋白結(jié)構(gòu),，竟能延緩病毒的擴散，這項發(fā)現(xiàn)也許能作為科學(xué)家預(yù)防下一次流感的警示,。
美國疾病管制及預(yù)防中心(Centers for Disease and Prevention)的科學(xué)家培養(yǎng)了一批1918年的H1N1流感病毒,，但他們將病毒外殼上hemagglutinin蛋白的兩個胺基酸改變，再將這些病毒滴到雪貂的鼻子(利用雪貂作為宿主是因為它的感染和傳播方式與人類很相似),。受到H1N1病毒感染的雪貂仍會生病或死亡,，但很明顯的，牠們并不會感染隔壁籠的雪貂,，這項發(fā)現(xiàn)發(fā)表于2月2日的Science期刊,。
到底為什么會這樣呢？一般情況下，病毒是由咳嗽或打噴嚏的飛沫所傳播,，而被改過的H1N1病毒感染的雪貂,，竟不會打噴嚏。研究人員認(rèn)為當(dāng)新的流感病毒造成大流行時,，會由病毒外殼上的hemagglutinin蛋白附著到人類的鼻子或氣管的黏膜細(xì)胞上,，只要打噴嚏病毒就得以傳播。
雖然H5N1病毒在全世界仍造成至少164人死亡,，但令人感到欣慰的是,，此病毒比較喜歡附著在禽類的腸道內(nèi)，且目前并無法以人傳人的方式傳播,。美國范德保大學(xué)(Vanderbilt University)的流行病學(xué)專家William Schaffner博士說：「研究流感病毒是一個很重要又精細(xì)的任務(wù),。」研究人員的下一步將要研究改變H5N1的hemagglutinin蛋白質(zhì)結(jié)構(gòu),，以觀察H5N1病毒在hemagglutinin被改變后是否與H1N1病毒有一樣的結(jié)果,。
部分英文原文：
A Two-Amino Acid Change in the Hemagglutinin of the 1918 Influenza Virus Abolishes Transmission
Terrence M. Tumpey,1* Taronna R. Maines,1 Neal Van Hoeven,1 Laurel Glaser,2 Alicia Solórzano,2 Claudia Pappas,1,2 Nancy J. Cox,1 David E. Swayne,3 Peter Palese,2 Jacqueline M. Katz,1 Adolfo García-Sastre2
The 1918 influenza pandemic was a catastrophic series of virus outbreaks that spread across the globe. Here, we show that only a modest change in the 1918 influenza hemagglutinin receptor binding site alters the transmissibility of this pandemic virus. Two amino acid mutations that cause a switch in receptor binding preference from the human -2,6 to the avian -2,3 sialic acid resulted in a virus incapable of respiratory droplet transmission between ferrets but that maintained its lethality and replication efficiency in the upper respiratory tract. Furthermore, poor transmission of a 1918 virus with dual -2,6 and -2,3 specificity suggests that a predominant human -2,6 sialic acid binding preference is essential for optimal transmission of this pandemic virus. These findings confirm an essential role of hemagglutinin receptor specificity for the transmission of influenza viruses among mammals.
1 Influenza Branch, Mailstop G-16, Division of Viral and Ricksettial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333, USA.
2 Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
3 Southeast Poultry Research Laboratory, Agricultural Research Laboratory, U.S. Department of Agriculture, 934 College Station Road, Athens, GA 30606, USA.
