Figure 1.

Activities of the macrocyclic peptides in the cell-based PD-1/PD-L1 immune checkpoint assay. Antigen presenting cells (APC) were seeded on culture plates and overlaid with PD-1 Effector Cells in the presence of different concentrations of therapeutic antibodies (A) or macrocyclic peptides (B). The activation of PD-1 Effector Cells, reflected by luciferase activity, was monitored by luminescence measurement. The data represent mean ± SD values from three independent experiments, normalized to the control vehicle-treated cells. For the regression analysis Hill equation was fitted to the experimental data and the half maximal effective concentrations (EC₅₀) and maximal relative luminescence values (RLU_max) were determined.