Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Microbiol Spectr. 2023 Aug 17;11(4):e0116623. doi: 10.1128/spectrum.01166-23. Epub 2023 Jul 5.
While primarily considered a respiratory pathogen, influenza A virus (IAV) is nonetheless capable of spreading to, and replicating in, numerous extrapulmonary tissues in humans. However, within-host assessments of genetic diversity during multicycle replication have been largely limited to respiratory tract tissues and specimens. As selective pressures can vary greatly between anatomical sites, there is a need to examine how measures of viral diversity may vary between influenza viruses exhibiting different tropisms in humans, as well as following influenza virus infection of cells derived from different organ systems. Here, we employed human primary tissue constructs emulative of the human airway or corneal surface, and we infected both with a panel of human- and avian-origin IAV, inclusive of H1 and H3 subtype human viruses and highly pathogenic H5 and H7 subtype viruses, which are associated with both respiratory disease and conjunctivitis following human infection. While both cell types supported productive replication of all viruses, airway-derived tissue constructs elicited greater induction of genes associated with antiviral responses than did corneal-derived constructs. We used next-generation sequencing to examine viral mutations and population diversity, utilizing several metrics. With few exceptions, generally comparable measures of viral diversity and mutational frequency were detected following homologous virus infection of both respiratory-origin and ocular-origin tissue constructs. Expansion of within-host assessments of genetic diversity to include IAV with atypical clinical presentations in humans or in extrapulmonary cell types can provide greater insight into understanding those features most prone to modulation in the context of viral tropism. Influenza A virus (IAV) can infect tissues both within and beyond the respiratory tract, leading to extrapulmonary complications, such as conjunctivitis or gastrointestinal disease. Selective pressures governing virus replication and induction of host responses can vary based on the anatomical site of infection, yet studies examining within-host assessments of genetic diversity are typically only conducted in cells derived from the respiratory tract. We examined the contribution of influenza virus tropism on these properties two different ways: by using IAV associated with different tropisms in humans, and by infecting human cell types from two different organ systems susceptible to IAV infection. Despite the diversity of cell types and viruses employed, we observed generally similar measures of viral diversity postinfection across all conditions tested; these findings nonetheless contribute to a greater understanding of the role tissue type contributes to the dynamics of virus evolution within a human host.
虽然甲型流感病毒（IAV）主要被认为是一种呼吸道病原体，但它仍然能够传播到并在人类的许多肺外组织中复制。然而，在多周期复制过程中对遗传多样性的宿主内评估在很大程度上仅限于呼吸道组织和标本。由于选择压力在解剖部位之间可能有很大差异，因此需要研究具有不同嗜性的流感病毒之间以及流感病毒感染来自不同器官系统的细胞后，病毒多样性的衡量标准可能如何变化。在这里，我们使用模仿人类气道或角膜表面的人原代组织构建体，并感染了一组人类和禽源 IAV，包括 H1 和 H3 亚型人类病毒以及高致病性 H5 和 H7 亚型病毒，这些病毒与人类感染后的呼吸道疾病和结膜炎都有关。虽然两种细胞类型都支持所有病毒的有效复制，但气道衍生的组织构建体比角膜衍生的构建体引起更多与抗病毒反应相关的基因诱导。我们使用下一代测序技术利用多种指标来检查病毒突变和群体多样性。除了少数例外，在呼吸道起源和眼起源组织构建体中同源病毒感染后，通常可以检测到具有可比病毒多样性和突变频率的措施。将遗传多样性的宿主内评估扩展到包括在人类或肺外细胞类型中表现出非典型临床表现的 IAV，可以更深入地了解在病毒嗜性背景下最容易发生调节的那些特征。 甲型流感病毒（IAV）可以感染呼吸道内外的组织，导致肺外并发症，如结膜炎或胃肠道疾病。控制病毒复制和诱导宿主反应的选择压力可能因感染部位的不同而有所不同，但研究宿主内遗传多样性评估的研究通常仅在源自呼吸道的细胞中进行。我们通过两种不同的方式研究了流感病毒嗜性对这些特性的贡献：使用与人类不同嗜性相关的 IAV，以及感染易受 IAV 感染的两个不同器官系统的人类细胞类型。尽管所使用的细胞类型和病毒种类繁多，但我们在所有测试条件下观察到感染后病毒多样性的一般相似措施；这些发现尽管如此，有助于更好地了解组织类型对人类宿主内病毒进化动态的作用。
