Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany.
Institute of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.
Sci Rep. 2016 Dec 22;6:39668. doi: 10.1038/srep39668.
Virus-host interactions in the respiratory epithelium during long term influenza virus infection are not well characterized. Therefore, we developed an air-liquid interface culture system for differentiated porcine respiratory epithelial cells to study the effect of virus-induced cellular damage. In our well-differentiated cells, α2,6-linked sialic acid is predominantly expressed on the apical surface and the basal cells mainly express α2,3-linked sialic acid. During the whole infection period, release of infectious virus was maintained at a high titre for more than seven days. The infected epithelial cells were subject to apoptosis resulting in the loss of ciliated cells together with a thinner thickness. Nevertheless, the airway epithelium maintained trans-epithelial electrical resistance and retained its barrier function. The loss of ciliated cells was compensated by the cells which contained the KRT5 basal cell marker but were not yet differentiated into ciliated cells. These specialized cells showed an increase of α2,3-linked sialic acid on the apical surface. In sum, our results help to explain the localized infection of the airway epithelium by influenza viruses. The impairment of mucociliary clearance in the epithelial cells provides an explanation why prior viral infection renders the host more susceptible to secondary co-infection by another pathogen.
在流感病毒长期感染期间，病毒-宿主相互作用在呼吸道上皮细胞中尚未得到很好的描述。因此，我们开发了一种用于分化的猪呼吸道上皮细胞的气液界面培养系统，以研究病毒诱导的细胞损伤的影响。在我们分化良好的细胞中，α2,6 连接的唾液酸主要在上皮细胞的顶端表面表达，而基底细胞主要表达α2,3 连接的唾液酸。在整个感染期间，感染性病毒的释放保持在高滴度超过七天。受感染的上皮细胞发生凋亡，导致纤毛细胞丢失和上皮层变薄。然而，气道上皮细胞保持跨上皮电阻并保留其屏障功能。纤毛细胞的丢失被含有 KRT5 基底细胞标志物但尚未分化为纤毛细胞的细胞所补偿。这些特化细胞在上皮细胞的顶端表面显示出α2,3 连接的唾液酸增加。总之，我们的结果有助于解释流感病毒对气道上皮细胞的局部感染。上皮细胞中黏液纤毛清除功能的损害解释了为什么先前的病毒感染使宿主更容易受到另一种病原体的继发合并感染。
