Department of Ophthalmology, University Hospital Tübingen, Tübingen, Germany.
Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany.
Graefes Arch Clin Exp Ophthalmol. 2023 Feb;261(2):435-446. doi: 10.1007/s00417-022-05776-6. Epub 2022 Aug 3.
To study the possibility of SARS-CoV-2 to infect human corneal cells and tissues under standard corneal culture conditions using explants of COVID-19 donors and primary cornea-derived epithelial cells.
Cornea isolated from deceased COVID-19 donors was cultured for 4 weeks, and SARS-CoV-2 replication was monitored by qRT-PCR. Furthermore, primary corneal epithelial cells from healthy donors were cultured ex vivo and infected with SARS-CoV-2 and human cytomegalovirus (HCMV) as a control. Infection status was assessed by western blotting and reporter gene expression using green fluorescent protein-expressing viral strains. ACE2 and TMPRSS2 receptor expression levels in cornea and epithelial cells were assessed by qRT-PCR.
We did not detect SARS-CoV-2 replication in 10 corneas isolated from deceased COVID-19 patients and cultured for 4 weeks, indicating absence of infection under natural conditions. Furthermore, high-titer SARS-CoV-2 infection of ex vivo cultured cornea-derived epithelial cells did not result in productive virus replication. In contrast, the same cells were highly permissive for HCMV. This phenotype could potentially be explained by low ACE2 and TMPRSS2 transcriptional activity in cornea and cornea-derived epithelial cells.
Our data suggest that cornea and limbal epithelial cells are refractory to productive SARS-CoV-2 infection. This could be due to the absence of robust receptor expression levels necessary for viral entry. This study adds further evidence to support the very low possibility of transmission of SARS-CoV-2 from an infected corneal transplant donor to a recipient in corneal organ cultures.
在标准角膜培养条件下，使用 COVID-19 供体的角膜外植体和原代角膜上皮细胞，研究 SARS-CoV-2 感染人角膜细胞和组织的可能性。
培养来自 COVID-19 死亡供体的角膜 4 周，并通过 qRT-PCR 监测 SARS-CoV-2 复制。此外，从健康供体中培养原代角膜上皮细胞，并通过感染 SARS-CoV-2 和人巨细胞病毒（HCMV）作为对照来感染。使用表达绿色荧光蛋白的病毒株通过 Western blot 和报告基因表达来评估感染状态。通过 qRT-PCR 评估角膜和上皮细胞中 ACE2 和 TMPRSS2 受体的表达水平。
我们未在从 COVID-19 死亡患者中分离并培养 4 周的 10 个角膜中检测到 SARS-CoV-2 复制，表明在自然条件下不存在感染。此外，高滴度 SARS-CoV-2 感染离体培养的角膜上皮细胞并未导致有复制能力的病毒复制。相反，相同的细胞对 HCMV 高度易感。这种表型可能可以通过角膜和角膜上皮细胞中 ACE2 和 TMPRSS2 转录活性低来解释。
我们的数据表明，角膜和缘上皮细胞对有复制能力的 SARS-CoV-2 感染具有抗性。这可能是由于缺乏病毒进入所需的强大受体表达水平。本研究进一步证明了从受感染的角膜移植供体到角膜器官培养中的受者传播 SARS-CoV-2 的可能性非常低。
