Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Proc Natl Acad Sci U S A. 2012 Mar 6;109(10):3944-9. doi: 10.1073/pnas.1119945109. Epub 2012 Feb 21.
Recent isolation of a novel swine-origin influenza A H3N2 variant virus [A(H3N2)v] from humans in the United States has raised concern over the pandemic potential of these viruses. Here, we analyzed the virulence, transmissibility, and receptor-binding preference of four A(H3N2)v influenza viruses isolated from humans in 2009, 2010, and 2011. High titers of infectious virus were detected in nasal turbinates and nasal wash samples of A(H3N2)v-inoculated ferrets. All four A(H3N2)v viruses possessed the capacity to spread efficiently between cohoused ferrets, and the 2010 and 2011 A(H3N2)v isolates transmitted efficiently to naïve ferrets by respiratory droplets. A dose-dependent glycan array analysis of A(H3N2)v showed a predominant binding to α2-6-sialylated glycans, similar to human-adapted influenza A viruses. We further tested the viral replication efficiency of A(H3N2)v viruses in a relevant cell line, Calu-3, derived from human bronchial epithelium. The A(H3N2)v viruses replicated in Calu-3 cells to significantly higher titers compared with five common seasonal H3N2 influenza viruses. These findings suggest that A(H3N2)v viruses have the capacity for efficient replication and transmission in mammals and underscore the need for continued public health surveillance.
最近从美国人体内分离出一种新型猪源甲型 H3N2 流感病毒 [A(H3N2)v]，引起了人们对这些病毒大流行潜力的关注。在这里，我们分析了从 2009 年、2010 年和 2011 年人类中分离出来的四种 A(H3N2)v 流感病毒的毒力、传染性和受体结合偏好。在接种 A(H3N2)v 的雪貂的鼻甲和鼻腔冲洗样本中检测到高滴度的传染性病毒。四种 A(H3N2)v 病毒都具有在共同饲养的雪貂之间有效传播的能力，2010 年和 2011 年的 A(H3N2)v 分离株通过呼吸道飞沫有效地传播给了新的雪貂。对 A(H3N2)v 的依赖剂量的糖基阵列分析表明，其主要结合α2-6-唾液酸化糖，类似于适应人类的流感 A 病毒。我们进一步在相关的细胞系 Calu-3 中测试了 A(H3N2)v 病毒的复制效率，该细胞系源自人支气管上皮。与五种常见的季节性 H3N2 流感病毒相比，A(H3N2)v 病毒在 Calu-3 细胞中的复制滴度显著更高。这些发现表明 A(H3N2)v 病毒具有在哺乳动物中有效复制和传播的能力，并强调需要持续进行公共卫生监测。
