Landolt Gabriele A, Karasin Alexander I, Schutten Melissa M, Olsen Christopher W
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, USA.
J Clin Microbiol. 2006 Feb;44(2):297-301. doi: 10.1128/JCM.44.2.297-301.2006.
Influenza A viruses cause pandemics at sporadic intervals. Pandemic viruses can potentially be introduced into the human population through in toto transfer of an avian influenza virus or through reassortment between avian and human strains. Pigs are believed to play a central role in the creation of pandemic viruses through reassortment because of their susceptibility to infection with both avian and human influenza viruses. However, we recently found that a human-lineage H3N2 influenza virus was highly restricted in its ability to infect pigs after intranasal inoculation. We hypothesized that this restricted infectivity phenotype was controlled by the hemagglutinin (HA) and neuraminidase (NA). To test this, we infected pigs with reverse genetics-created HA plus NA reassortant viruses. Specifically, introduction of the HA and NA genes of a contemporary H3N2 swine virus into the genetic background of the wholly human virus resulted in a significant increase in virus shedding and pathogenicity. These data indicate that the HA/NA can play important roles in controlling human influenza virus infectivity in pigs. The results further support the premise that a barrier exists to human influenza virus infection in pigs, which may limit the role of pigs in pandemic virus creation through reassortment of human and avian influenza viruses.
甲型流感病毒偶尔会引发大流行。大流行病毒有可能通过禽流感病毒的整体转移或通过禽源和人源毒株之间的重配进入人群。由于猪对禽流感病毒和人流感病毒均易感，因此人们认为猪在通过重配产生大流行病毒的过程中起着核心作用。然而，我们最近发现，一种人源谱系的H3N2流感病毒经鼻内接种后感染猪的能力受到高度限制。我们推测这种受限的感染表型受血凝素（HA）和神经氨酸酶（NA）控制。为了验证这一点，我们用反向遗传学构建的HA加NA重配病毒感染猪。具体而言，将当代H3N2猪病毒的HA和NA基因导入完全人源病毒的基因背景中，导致病毒排出量和致病性显著增加。这些数据表明，HA/NA在控制人流感病毒在猪体内的感染性方面可能发挥重要作用。结果进一步支持了猪存在人流感病毒感染障碍这一前提，这可能会限制猪在通过人禽流感病毒重配产生大流行病毒过程中的作用。
