Figure 6.

Measurement of affinities of recombinant BsDb to PD-1 and VEGF165. Binding curves of recombinant BsDb to VEGF165 (A) and PD-1 (B) tested using indirect ELISA; (C) The affinity constant was determined using the Beatty formula. [Ab]t and [Ab’]t represent the EC50 of high and low concentrations of antigen, respectively. PBS was used as a negative control; (D) Schematic diagram of sandwich ELISA; (E) Simultaneous binding of recombinant BsDb to both PD-1 and VEGF165 was evaluated using sandwich ELISA. PBS was used as a negative control. The experiments were performed in triplicate, and the mean values ± SD were presented.