Fig. 6. Potent neutralization of SARS-CoV-2 B.1.1.529 using combinations of antibodies.

(A) Lentiviruses pseudotyped with SARS-CoV-2 B.1.1.529 spike were incubated with serial dilutions of the indicated combination of antibodies, and IC₅₀ and IC₈₀ values were determined. Ranges are indicated with white (>10,000 ng/ml), light blue (>1000 to ≤10,000 ng/ml), yellow (>100 to ≤1000 ng/ml), orange (>50 to ≤100 ng/ml), red (>10 to ≤50 ng/ml), maroon (>1 to ≤10 ng/ml), and purple (≤1 ng/ml). (B) Neutralization IC₅₀ (ng/ml) values for each of the indicated cocktail (x axis) or its component antibodies. The IC₅₀ for first antibody is listed as mAb1 (black), and the second antibody is listed as mAb2 (gray) or cocktail (red). (C) Cryo-EM structure of B.1.1.529 spike in complex with antibodies A19-46.1 and B-182.1 at 3.86 Å resolution. (Left) Overall density map, with protomers colored light green, wheat, and light cyan. (Middle) All RBD are in up conformation, with both Fabs bound. (Right) Binding of one Fab (such as B1-182.1) induces RBD into the up conformation and potentially facilitates binding of the other Fab (such as A19-46.1), which only recognizes the up conformation of RBD. A19-46.1 and B-182.1 are in orange and olive, respectively. The contour level of cryo-EM map is 6.5σ.