Fig. 1: Characterization of PDCoV neutralizing antibodies.

A Schematic representation of the PDCoV S protein, with domain A, domain B and the transmembrane domain (TM) labeled. B ELISA analysis showing mAb binding to immobilized prefusion PDCoV S trimer (left panel), S1B domain (middle panel) and S1A domain (right panel). C Binding kinetics of S-specific mAbs to PDCoV S1, measured through Bio-Layer Interferometry (BLI). Monoclonal antibodies were immobilized using anti-human Fc biosensors, and association and dissociation were observed with serially diluted PDCoV S1B, allowing calculation of equilibrium dissociation constants (KD). The experiment was conducted twice, with one representative experiment shown. D Neutralization of authentic PDCoV in Huh7 cells. PDCoV was preincubated with 3-fold serially diluted mAbs for 60 min before infecting Huh7 cells. Infection was quantified 15 h post infection by immunofluorescence microscopy. E ELISA-based receptor binding inhibition assay. PDCoV S1B, preincubated with serially diluted S mAbs, was added to a plate coated with soluble aminopeptidase N (APN). The interaction was quantified using HRP-conjugated antibody targeting the C-terminal Strep-tag fused to PDCoV S1B. Results represent the mean (±SD) from two independent experiments with at least two technical replicates. Source data are provided as a Source Data file. F EC50 (half-maximal effective concentrations) and IC50 (half-maximal inhibitory concentrations) values for each mAb calculated from the binding and neutralization curves displayed in (B) and (D), respectively.