Fig. 5: Characteristics of recombinant mAbs derived from SARS-CoV-2 naive donors.

a WT SARS-CoV-2 RBD binding by five recombinant mAbs were assessed by BLI. Black and colored lines represent experimentally recorded sensorgram traces and corresponding fits. Twofold serially diluted RBD solutions (200 nM to 3.125 nM) were used in the BLI assays. b Binding of mAb H18 to SARS-CoV-1, Pangolin CoV GD1, and Bat CoV RaTG13 RBDs were measured by BLI. Kinetic parameters for a and b are summarized in Supplementary Table 3. c Neutralization activities (data are presented as mean values ± SD, n = 3) of mAb H18 towards SARS-CoV-2 authentic viruses in cell culture. d Structures of S-GSAS/6 P S-trimers in complex with H18 Fabs in different stoichiometries and conformations. e Structures of S-GSAS/6 P S-trimers or S1s in complex with H18 Fabs and R1-32 Fabs. Structures in d, e are low-pass filtered to 12 Å to reveal flexible regions (also see Fig. S2). H18 Fab, NTD, and RBD are highlighted in magenta, blue, cyan, respectively; other structures are colored gray. f Detailed H18 epitope structure. H18-H and H18-L chains are colored in magenta and purple; CDR loops are indicated, selected interacting residues between RBD and H18 are shown and indicated; thick and thin dashed lines indicate cation-π interactions and hydrogen bonds. Source data for c are provided as a Source Data file.