Ma Wenjun, Vincent Amy L, Gramer Marie R, Brockwell Christy B, Lager Kelly M, Janke Bruce H, Gauger Phillip C, Patnayak Devi P, Webby Richard J, Richt Jürgen A
Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Proc Natl Acad Sci U S A. 2007 Dec 26;104(52):20949-54. doi: 10.1073/pnas.0710286104. Epub 2007 Dec 18.
Although viruses of each of the 16 influenza A HA subtypes are potential human pathogens, only viruses of the H1, H2, and H3 subtype are known to have been successfully established in humans. H2 influenza viruses have been absent from human circulation since 1968, and as such they pose a substantial human pandemic risk. In this report, we isolate and characterize genetically similar avian/swine virus reassortant H2N3 influenza A viruses isolated from diseased swine from two farms in the United States. These viruses contained leucine at position 226 of the H2 protein, which has been associated with increased binding affinity to the mammalian alpha2,6Gal-linked sialic acid virus receptor. Correspondingly, the H2N3 viruses were able to cause disease in experimentally infected swine and mice without prior adaptation. In addition, the swine H2N3 virus was infectious and highly transmissible in swine and ferrets. Taken together, these findings suggest that the H2N3 virus has undergone some adaptation to the mammalian host and that their spread should be very closely monitored.
虽然16种甲型流感血凝素（HA）亚型的每种病毒都是潜在的人类病原体，但已知只有H1、H2和H3亚型病毒曾在人类中成功定殖。自1968年以来，H2流感病毒已不在人类中传播，因此它们构成了重大的人类大流行风险。在本报告中，我们分离并鉴定了从美国两个农场的患病猪中分离出的基因相似的禽/猪病毒重组H2N3甲型流感病毒。这些病毒在H2蛋白的第226位含有亮氨酸，这与对哺乳动物α2,6-连接唾液酸病毒受体的结合亲和力增加有关。相应地，H2N3病毒在未经预先适应的情况下就能在实验感染的猪和小鼠中引起疾病。此外，猪H2N3病毒在猪和雪貂中具有传染性且极易传播。综上所述，这些发现表明H2N3病毒已对哺乳动物宿主进行了一些适应，其传播应受到密切监测。
