Fig. 1 | Cellular & Molecular Immunology

Fig. 1

From: Key residues of the receptor binding motif in the spike protein of SARS-CoV-2 that interact with ACE2 and neutralizing antibodies

Fig. 1

Both the SARS-CoV-2 RBD and SARS-CoV RBD bind to hACE2. a Receptor-dependent infection of SARS-CoV-2 and SARS-CoV pseudo-typed virus entry into hACE2+ 293 T cells. 293T cells stably expressing hACE2 were infected with SARS-CoV-2 or SARS-CoV pseudo-typed viruses, and the cells were harvested to detect the luciferase activity. Fold changes were calculated by comparison to the levels in the uninfected cells. VSV pseudo-typed viruses were included as controls. b Syncytia formation between S protein- and hACE2-expressing cells. 293T cells transfected with hACE2 plasmid were mixed at a 1:1 ratio with 293T cells transfected with plasmid encoding S protein from SARS-CoV-2 (bottom left) or SARS-CoV (bottom right). As controls, 293T cells transfected with an empty plasmid were either mixed at a 1:1 ratio with 293T cells transfected with the hACE2 plasmid (top row), S protein from SARS-CoV-2 (middle left) or SARS-CoV (middle right). Images were photographed at ×20 magnification. Representative images are shown. c Dose-dependent binding of the SARS-CoV-2 RBD to soluble hACE2 as determined by ELISA. The binding of both the SARS-CoV-2 RBD and SARS-CoV RBD with an Fc tag on hACE2 was tested. Human Fc was included as a control. Data are presented as the mean OD450 ± s.e.m. (n = 2). d Binding profiles of the SARS-CoV-2 RBD and SARS-CoV RBD to the soluble hACE2 receptor measured by biolayer interferometry in an Octet RED96 instrument. The biotin-conjugated hACE2 protein was captured by streptavidin that was immobilized on a chip and tested for binding with gradient concentrations of the soluble RBD of S proteins from SARS CoV and SARS CoV-2. Binding kinetics were evaluated using a 1:1 Langmuir binding model by ForteBio Data Analysis 9.0 software

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