Figure 4.
MERS stem-targeted mAbs neutralize authentic MERS-CoV
(A–C) Binding of Fab22 to MERS-CoV S (A), SARS-CoV S (B), and SARS-CoV-2 S (C) assessed by surface plasmon resonance. Binding data are shown as black lines, and the best fit to a 1:1 binding model is shown as red lines.
(D) IgG22 and IgG72 demonstrated concentration-dependent neutralization of MERS-CoV infectivity. Other SS.V1 elicited mAbs shown lacked detectable neutralizing activity against MERS-CoV. mAbs IgG20, IgG22, and IgG72 were tested in duplicate, and remaining mAbs were tested once. Neutralizing mAb G4 was included as a positive control and tested in triplicate.
(E) Neither IgG22 nor IgG72 exhibited detectable neutralization of SARS-CoV-2. mAb S309, which neutralizes SARS-CoV-2, was included as a positive control. IgG22 and IgG72 were tested once, and S309 was tested in duplicate.
(F) Representative 2D class averages and cryo-EM map of Fab22 bound to MERS S-2P. The map is colored by local resolution. The side view and top-down view of the Gaussian filtered maps indicate distinct Fab volumes.