Fig. 4.

a ELISA results showed the binding specificity of phages and PD-L1 antigen. All tested samples have binding specificity but only eight clones (B10, B30, B31, B36, B38, B46, B84, and B129) were chosen after ELISA and sequence analysis. Three samples (B30, C36, and B129) were further processed for scFv expression after the successful construction of a recombinant vector. OD: optical density. b The binding affinity of eight positive phages with different concentration of PD-L1 by ELISA. PD-L1 protein was coated at different concentration in 96 wells plate and phages (10¹⁰) were added as the primary antibody. BSA was used as a control for non-specific binding