Coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide since its outbreak in December 2019, and World Health Organization declared it as a pandemic on March 11, 2020. SARS-CoV-2 is highly contagious and is transmitted through airway epithelial cells as the first gateway. SARS-CoV-2 is detected by nasopharyngeal or oropharyngeal swab samples, and the viral load is significantly high in the upper respiratory tract. The host cellular receptors in airway epithelial cells, including angiotensin-converting enzyme 2 and transmembrane serine protease 2, have been identified by single-cell RNA sequencing or immunostaining. The expression levels of these molecules vary by type, function, and location of airway epithelial cells, such as ciliated cells, secretory cells, olfactory epithelial cells, and alveolar epithelial cells, as well as differ from host to host depending on age, sex, or comorbid diseases. Infected airway epithelial cells by SARS-CoV-2 in ex vivo experiments produce chemokines and cytokines to recruit inflammatory cells to target organs. Same as other viral infections, IFN signaling is a critical pathway for host defense. Various studies are underway to confirm the pathophysiological mechanisms of SARS-CoV-2 infection. Herein, we review cellular entry, host-viral interactions, immune responses to SARS-CoV-2 in airway epithelial cells. We also discuss therapeutic options related to epithelial immune reactions to SARS-CoV-2.

中文翻译：

---

气道上皮细胞的 SARS-CoV-2 感染。

由严重急性呼吸综合征冠状病毒2（SARS-CoV-2）引起的2019年冠状病毒病自2019年12月爆发以来一直在全球范围内传播，世界卫生组织于2020年3月11日宣布其为大流行病。SARS-CoV-2是传染性极强，以气道上皮细胞为第一门户传播。通过鼻咽或口咽拭子样本检测到SARS-CoV-2，上呼吸道病毒载量明显较高。气道上皮细胞中的宿主细胞受体，包括血管紧张素转换酶 2 和跨膜丝氨酸蛋白酶 2，已通过单细胞 RNA 测序或免疫染色进行了鉴定。这些分子的表达水平因气道上皮细胞（例如纤毛细胞、分泌细胞、嗅觉上皮细胞和肺泡上皮细胞）的类型、功能和位置而异，并且因宿主的年龄、性别、年龄而异。或合并症。在离体实验中，被 SARS-CoV-2 感染的气道上皮细胞会产生趋化因子和细胞因子，将炎症细胞招募到靶器官。与其他病毒感染一样，干扰素信号传导是宿主防御的关键途径。正在进行各种研究来确认 SARS-CoV-2 感染的病理生理机制。在此，我们回顾了气道上皮细胞中的细胞进入、宿主与病毒的相互作用以及对 SARS-CoV-2 的免疫反应。我们还讨论了与 SARS-CoV-2 上皮免疫反应相关的治疗方案。