•Monoclonal antibody 4G8C11 exhibits stable and high affinity for human ACE2 receptor.•4G8C11 blocks SARS-CoV-2 and variant binding to human ACE2.•4G8C11 has no significant inhibitory activity ...against human ACE2 receptor activity.
Vaccines and antibodies that specifically target or neutralize components of the SARS-CoV-2 virus are effective in prevention and treatment of human patients with SARS-CoV-2 infection. However, vaccines and SARS-CoV-2 neutralization antibodies target a subset of epitopes of viral proteins, and the fast evolution of the SARS-CoV-2 virus and the continuing emergence of SARS-CoV-2 variants confer SARS-CoV-2 immune escape from these therapies. ACE2 is the human cell receptor that serves as the entry point for SARS-CoV-2 into human cells and thus is the gatekeeper for SARS-CoV-2 infection of humans. We report here the development of 4G8C11, an anti-human ACE2 receptor monoclonal antibody that recognizes ACE2 on human cell surfaces. We determined that 4G8C11 blocks SARS-CoV-2 and variant infection of ACE2+ human cells. Furthermore, 4G8C11 has minimal effects on ACE2 receptor activity. 4G8C11 is therefore a monoclonal antibody for ACE2 receptor detection and potentially an effective immunotherapeutic agent for SARS-CoV-2 and variants.
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From the beginning of 2002 and 2012, severe respiratory syndrome coronavirus (SARS‐CoV) and Middle East respiratory syndrome coronavirus (MERS‐CoV) crossed the species barriers to infect humans, ...causing thousands of infections and hundreds of deaths, respectively. Currently, a novel coronavirus (SARS‐CoV‐2), which has become the cause of the outbreak of Coronavirus Disease 2019 (COVID‐19), was discovered. Until 18 February 2020, there were 72 533 confirmed COVID‐19 cases (including 10 644 severe cases) and 1872 deaths in China. SARS‐CoV‐2 is spreading among the public and causing substantial burden due to its human‐to‐human transmission. However, the intermediate host of SARS‐CoV‐2 is still unclear. Finding the possible intermediate host of SARS‐CoV‐2 is imperative to prevent further spread of the epidemic. In this study, we used systematic comparison and analysis to predict the interaction between the receptor‐binding domain (RBD) of coronavirus spike protein and the host receptor, angiotensin‐converting enzyme 2 (ACE2). The interaction between the key amino acids of S protein RBD and ACE2 indicated that, other than pangolins and snakes, as previously suggested, turtles (Chrysemys picta bellii, Chelonia mydas, and Pelodiscus sinensis) may act as the potential intermediate hosts transmitting SARS‐CoV‐2 to humans.
Highlights
The critical residues of S protein RBD binding with ACE2 indicated the potential intermediate hosts transmitting SARS‐CoV‐2 to humans.
This article reviews the correlation between angiotensin‐converting enzyme 2 (ACE2) and severe risk factors for coronavirus disease 2019 (COVID‐19) and the possible mechanisms. ACE2 is a crucial ...component of the renin‐angiotensin system (RAS). The classical RAS ACE‐Ang II‐AT1R regulatory axis and the ACE2‐Ang 1‐7‐MasR counter‐regulatory axis play an essential role in maintaining homeostasis in humans. ACE2 is widely distributed in the heart, kidneys, lungs, and testes. ACE2 antagonizes the activation of the classical RAS system and protects against organ damage, protecting against hypertension, diabetes, and cardiovascular disease. Similar to SARS‐CoV, SARS‐CoV‐2 also uses the ACE2 receptor to invade human alveolar epithelial cells. Acute respiratory distress syndrome (ARDS) is a clinical high‐mortality disease, and ACE2 has a protective effect on this type of acute lung injury. Current research shows that the poor prognosis of patients with COVID‐19 is related to factors such as sex (male), age (>60 years), underlying diseases (hypertension, diabetes, and cardiovascular disease), secondary ARDS, and other relevant factors. Because of these protective effects of ACE2 on chronic underlying diseases and ARDS, the development of spike protein‐based vaccine and drugs enhancing ACE2 activity may become one of the most promising approaches for the treatment of COVID‐19 in the future.
Research Highlights
ACE2 plays an important role in renin‐angiotensin system and homeostasis.
ACE2 has a protective effect on acute lung injury and for the COVID‐19 patients with underlying diseases.
The development of spike protein‐based vaccine and drugs enhancing ACE2 activity may become one of the most promising approaches for the treatment of COVID‐19.
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.
Cell entry mechanisms of SARS-CoV-2 Shang, Jian; Wan, Yushun; Luo, Chuming ...
Proceedings of the National Academy of Sciences - PNAS,
05/2020, Letnik:
117, Številka:
21
Journal Article
Recenzirano
Odprti dostop
A novel severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2) is causing the global coronavirus disease 2019 (COVID-19) pandemic. Understanding how SARS-CoV-2 enters human cells is a ...high priority for deciphering its mystery and curbing its spread. A virus surface spike protein mediates SARS-CoV-2 entry into cells. To fulfill its function, SARS-CoV-2 spike binds to its receptor human ACE2 (hACE2) through its receptor-binding domain (RBD) and is proteolytically activated by human proteases. Here we investigated receptor binding and protease activation of SARS-CoV-2 spike using biochemical and pseudovirus entry assays. Our findings have identified key cell entry mechanisms of SARS-CoV-2. First, SARS-CoV-2 RBD has higher hACE2 binding affinity than SARS-CoV RBD, supporting efficient cell entry. Second, paradoxically, the hACE2 binding affinity of the entire SARS-CoV-2 spike is comparable to or lower than that of SARS-CoV spike, suggesting that SARS-CoV-2 RBD, albeit more potent, is less exposed than SARS-CoV RBD. Third, unlike SARS-CoV, cell entry of SARS-CoV-2 is preactivated by proprotein convertase furin, reducing its dependence on target cell proteases for entry. The high hACE2 binding affinity of the RBD, furin preactivation of the spike, and hidden RBD in the spike potentially allow SARS-CoV-2 to maintain efficient cell entry while evading immune surveillance. These features may contribute to the wide spread of the virus. Successful intervention strategies must target both the potency of SARS-CoV-2 and its evasiveness.
A remarkable number of SARS‐CoV‐2 variants and other as yet unmonitored lineages harbor amino‐acid substitutions with the potential to modulate the interface between the spike receptor‐binding domain ...(RBD) and its receptor ACE2. The naturally occurring Q498Y substitution, which is present in currently circulating SARS‐CoV‐2 variants, has drawn the attention of several investigations. While computational predictions and in vitro binding studies suggest that Q498Y increases the binding affinity of the spike protein for ACE2, experimental in vivo models of infection have shown that a triple mutant carrying the Q498Y replacement is fatal in mice. To accurately characterize the binding kinetics of the RBD Q498Y–ACE2 interaction, biolayer interferometry analyses were performed. A significant enhancement of the RBD–ACE2 binding affinity relative to a reference SARS‐CoV‐2 variant of concern carrying three simultaneous replacements was observed. In addition, the RBD Q498Y mutant bound to ACE2 was crystallized. Compared with the structure of its wild‐type counterpart, the RBD Q498Y–ACE2 complex reveals the conservation of major hydrogen‐bond interactions and a more populated, nonpolar set of contacts mediated by the bulky side chain of Tyr498 that collectively lead to this increase in binding affinity. In summary, these studies contribute to a deeper understanding of the impact of a relevant mutation present in currently circulating SARS‐CoV‐2 variants which might lead to stronger host–pathogen interactions.
The structural bases underpinning the higher affinity for the human receptor ACE2 conferred by a naturally occurring mutation (Q498Y) in the SARS‐CoV‐2 spike receptor‐binding domain are described.
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