Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA.
Tianhe Stem Cell Biotechnologies Inc., Paramus, New Jersey, USA.
Cytometry A. 2023 Feb;103(2):136-145. doi: 10.1002/cyto.a.24285. Epub 2020 Dec 16.
Angiotensin-converting enzyme-2 (ACE2) has been recognized as the binding receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Flow cytometry demonstrated that there was little to no expression of ACE2 on most of the human peripheral blood-derived immune cells including CD4 T, CD8 T, activated CD4 /CD8 T, Tregs, Th17, NKT, B, NK cells, monocytes, dendritic cells, and granulocytes. There was no ACE2 expression on platelets and very low level of ACE2 protein expression on the surface of human primary pulmonary alveolar epithelial cells. The ACE2 expression was markedly upregulated on the activated type 1 macrophages (M1). Immunohistochemistry demonstrated high expressions of ACE2 on human tissue macrophages, such as alveolar macrophages, Kupffer cells within livers, and microglial cells in brain at steady state. The data suggest that alveolar macrophages, as the frontline immune cells, may be directly targeted by the SARS-CoV-2 infection and therefore need to be considered for the prevention and treatment of COVID-19.
血管紧张素转换酶 2（ACE2）已被确认为严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的结合受体。流式细胞术表明，在大多数人类外周血来源的免疫细胞中，包括 CD4 T、CD8 T、活化的 CD4/CD8 T、Tregs、Th17、NKT、B、NK 细胞、单核细胞、树突状细胞和粒细胞，ACE2 的表达很少或几乎没有。血小板上没有 ACE2 表达，人原发性肺肺泡上皮细胞表面的 ACE2 蛋白表达水平也很低。活化的 1 型巨噬细胞（M1）上的 ACE2 表达明显上调。免疫组织化学显示，在稳态下，人组织巨噬细胞（如肺泡巨噬细胞、肝脏内的枯否细胞和大脑中的小胶质细胞）上高表达 ACE2。这些数据表明，肺泡巨噬细胞作为一线免疫细胞，可能直接成为 SARS-CoV-2 感染的靶细胞，因此需要考虑用于 COVID-19 的预防和治疗。
