<p>Binding of sarbceovirus RBDs with monoclonal antibodies isolated from SARS-CoV-2 breakthrough infections.</p>

The residues of interest on the RBD are highlighted on the cartoon representation or of the surface. A critical interacting residue of the VA14_26, E106, is highlighted. This residue is attracted to the positively charged surface of the WIV-1 RBD.

Homologous residues present in other RBD, decrease (Rco319) or reverse (RhGB07) this positive charge surface that decreases affinity of the VA14_26 antibody for these RBDs. <b>(C)</b> Each plot shows a single mAb binding, coloured by its designated antibody competition group (Group 1 = purple, Group 2 = orange, Group 3 = red, Group 3.5 = blue, Group 4 = green, Group 8 = non-RBD, NTD-specific) in an ELISA using purified RacCS203 RBD.

The curves were calculated using a least-squares regression non-linear fit. Binding (EC₅₀, µg/ml) titres are shown for each mAb against RacCS203, with limits of detection indicated (lower limit: <0.08g/ml upper limit: 5 µg/ml). Red boxes indicate mAbs that exhibit high binding with all sarbecoviruses tested. <b>(C)</b> Representative SPR kinetics binding curves showing the association and dissociation of mAb VA14_26 with bat sarbecovirus RBDs.

Each line represents a RBD concentration, starting at 5 µg/ml and titrated 2-fold (8 dilutions). Calculated K_D values are also shown. The data underlying this Figure can be found in <a href="plosbiology.org/article/info:doi/10.1371/journal.pbio.3003944#pbio.3003944.s017" target="_blank">S1 Data</a>.</p> <p>(TIF)</p>