Extended Data Fig. 4: Breadth of antibody binding across sarbecoviruses.

a, Phylogenetic relationship of sarbecovirus RBDs inferred from aligned nucleotide sequences, with the four sarbecovirus clades labelled in separate colours used throughout the text. Node support values are bootstrap support values. b, Breadth of sarbecovirus binding by each antibody to a panel of yeast-displayed sarbecovirus RBDs. Data as in Fig. 1d, with the addition of secondary “full escape” selection data for S2H97, S2H13, and S2H14 (0 ng ml⁻¹ wild-type control as shown in Extended Data Fig. 2b, c), enabling differentiation of RBDs with intermediate binding (for example, S2H97/RsSHC014) versus complete loss of binding. Escape fractions are calculated as the mean of replicate barcoded genotypes internal to the library. Median number of barcodes per RBD is 249, with a range of 104 to 566. The median SEM across escape fraction measurements is 0.019, with a range of 0.00005 to 0.038 across all RBD/antibody pairs. c, Flow cytometry detection of antibody binding to isogenic yeast-displayed RBD variants. d, Flow cytometry detection of antibody binding to mammalian-surface displayed spikes. e, ELISA binding of antibody to purified RBD proteins. f, SPR measurement of binding of cross-reactive antibodies (Fab) and human ACE2 to select sarbecovirus RBDs. NB, no binding; NT, not tested. Values from single replicates. g, S2H97 neutralization of VSV pseudotyped with select sarbecovirus spikes, with entry measured in ACE2-transduced BHK-21 cells. Curves are representative of two independent experiments. Points represent means, error bars standard deviation from three technical replicates, and IC₅₀ geometric mean of experiments. IC₅₀ values are not comparable to other experiments on Vero E6 cells (for example, Fig. 2c) due to ACE2 overexpression and its impact on S2H97 neutralization. h, Alignment of germline-reverted and mature S2H97 heavy- (top) and light-chain (bottom) amino acid sequences. CDR sequences shown in grey box. Heat map overlay indicates the predicted energetic contribution of antibody paratope residues from the crystal structure. i, Binding of germline-reverted and mature S2H97 to select sarbecovirus RBDs as measured by SPR. j, Neutralization experiment of select sarbecoviruses by S2E12 (spike-pseudotyped VSV on 293T-ACE2 cells). Details as in Fig. 3c. k, Alignment of germline-reverted and mature S2E12. Details as in h. l, Binding of germline-reverted and mature S2E12 to select sarbecovirus RBDs as measured by SPR.