Fig. 1
From: Preclinical evaluation of a novel antibody–drug conjugate OBI-992 for Cancer therapy
Investigation of the R4702 binding epitope and binding affinity to TROP2 protein and TROP-2 expressing cells. (A) Evaluation of R4702 binding to different fragments of the extracellular domain (ECD) of TROP2. (B) Investigation of the specific binding epitope of R4702 in the ECD. ELISA assays were performed for both (A) and (B) by incubating the indicated peptides with R4702 followed by measuring the absorbances at 450 nM. (C) The antibody binding region in TROP2 structure (PDB 7E5M). According to the epitope mapping, the R4702 antibody binding to the CRD2.1 (sequence 32–57), indicated by violet color. (D-F) Competition binding assays. BxPC3 cells were pre-treated with the antibody indicated in the X-axis followed by incubation with fluorescein-sacituzumab (D), fluorescein-datopotamab (E), or fluorescein-R4702 (F). (G) Monitoring the binding affinity of TROP2 antibodies to TROP2 protein by surface plasmon resonance. Ka, Association rate constant; KD, equilibrium dissociation constant; Kd, dissociation rate. MFI, mean fluorescence intensity.
