Bakre Abhijeet, Sweeney Ryan, Espinoza Edna, Suarez David L, Kapczynski Darrell R
Exotic and Emerging Avian Viral Disease Research Unit, Southeast Poultry Research Laboratories, US National Poultry Research Center, United States Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA.
Viruses. 2025 Mar 31;17(4):507. doi: 10.3390/v17040507.
During the COVID-19 pandemic, severe acute respiratory syndrome coronavirus 2 (SC2) infection was confirmed in various animal species demonstrating a wide host range of the virus. Prior studies have shown that the ACE2 protein is the primary receptor used by the virus to gain cellular entry and begin the replication cycle. In previous studies, we demonstrated that human and various bat ACE2 proteins can be utilized by SC2 viruses for entry. Bats are a suspected natural host of SC2 because of genetic homology with other bat coronaviruses. In this work, we demonstrate that expression of ACE2 genes from the common vampire bat (CVB) () and the pallid bat (PB) (), supports infection and replication of some SC2 viruses in cell culture. Two cell lines were produced, CVB-ACE2 and PB-ACE2, expressing ACE2 from these bat species along with human TMPRSS2, in a model previously established using a non-permissive chicken DF-1 cell line. Results demonstrate that the original Wuhan lineage (WA1) virus and the Delta variant were able to infect and replicate in either of the bat ACE2 cell lines. In contrast, the Lambda and Omicron variant viruses infected both cell lines, but viral titers did not increase following infection. Viral detection using immunofluorescence demonstrated abundant spike (S) protein staining for the WA1 and Delta variants but little signal for the Lambda and Omicron variants. These studies demonstrate that while ACE2 from CVB and PB can be utilized by SC2 viruses to gain entry for infection, later variants (Lambda and Omicron) replicate poorly in these cell lines. These observations suggest more efficient human adaption in later SC2 variants that become less fit for replication in other animal species.
在新冠疫情期间，在多种动物物种中证实了严重急性呼吸综合征冠状病毒2（SC2）感染，这表明该病毒具有广泛的宿主范围。先前的研究表明，ACE2蛋白是该病毒用于进入细胞并开始复制周期的主要受体。在之前的研究中，我们证明了人类和各种蝙蝠的ACE2蛋白可被SC2病毒用于进入细胞。由于与其他蝙蝠冠状病毒存在基因同源性，蝙蝠被怀疑是SC2的天然宿主。在这项研究中，我们证明了普通吸血蝙蝠（CVB）（）和苍白蝙蝠（PB）（）的ACE2基因表达，支持某些SC2病毒在细胞培养中的感染和复制。我们构建了两种细胞系，CVB-ACE2和PB-ACE2，它们在先前使用非许可性鸡DF-1细胞系建立的模型中表达来自这些蝙蝠物种的ACE2以及人类跨膜丝氨酸蛋白酶2（TMPRSS2）。结果表明，原始的武汉谱系（WA1）病毒和德尔塔变种能够在任何一种蝙蝠ACE2细胞系中感染和复制。相比之下，拉姆达和奥密克戎变种病毒能够感染这两种细胞系，但感染后病毒滴度并未增加。使用免疫荧光进行病毒检测显示，WA1和德尔塔变种有丰富的刺突（S）蛋白染色，而拉姆达和奥密克戎变种的信号较弱。这些研究表明，虽然CVB和PB的ACE2可被SC2病毒用于进入细胞进行感染，但后来的变种（拉姆达和奥密克戎）在这些细胞系中的复制能力较差。这些观察结果表明，在后来的SC2变种中，人类适应性更强，而在其他动物物种中的复制适应性则降低。
