ACE2 Receptor Usage across Animal Species by SARS-CoV-2 Variants

Abstract

We analyzed the receptor-binding activity and infectivity of 6 representative SARS-CoV-2 lineages in cell lines expressing angiotensin-converting enzyme 2 proteins from 54 different animal species. All viruses demonstrated infectivity in a broad range of species. Susceptible animal species could serve as natural reservoirs or intermediate hosts for SARS-CoV-2.

Keywords: ACE2; COVID-19; One Health; SARS-CoV-2; coronavirus disease; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.

Figure 1

Sequence comparison of ACE2 proteins among 54 animal species with phylogenetic tree of ACE2 proteins in study of ACE2 receptor usage across animal species by SARS-CoV-2 variants. Protein sequence of ACE2 from various species are aligned at residues in the SARS-CoV-2 spike protein binding interface. Percent identity to human ACE2 was calculated by pairwise alignment of individual ACE2s to human ACE2. Residues differing from human ACE2 residues are highlighted in yellow. Scale bar indicates the number of amino acid substitutions based on ACE2 protein sequences. ACE2, angiotensin-converting enzyme 2.

Figure 2

Heatmaps showing the binding strength of spike proteins (A) and infectivity of SARS-CoV-2 variants (B) to cells expressing ACE2 proteins from 54 animal species in study of ACE2 receptor usage across animal species by SARS-CoV-2 variants. The binding of the spike proteins to ACE2 was normalized to the reference group of index (wild-type) virus spike protein and human ACE2 cells (defined as 1) for both 2 µg/mL and 20 µg/mL spike protein concentrations. The representative data from 3 independent experiments are shown. The infectivity of SARS-CoV-2 reporter viruses was also normalized to the reference group of index virus and human ACE2 cells (defined as 1). The ratios, relative to the index virus and human ACE2 cells, are displayed as colors ranging from white to red. The experiment was performed in triplicate and the average was used in the heatmap. ACE2, angiotensin-converting enzyme 2.