CAY10774 is an inhibitor of the protein-protein interaction between programmed cell death 1 (PD-1) and its ligand PD-L1 (IC50= 15 nM in a homologous time-resolved fret (HTRF) assay).1It increases the activation of Jurkat cells expressing PD-1 in co-culture with artificial antigen-presenting cells (aAPCs) expressing PD-L1 (EC50= 6.6 μM in a reporter assay). CAY10774 increases surface expression of PD-1 on primary human CD4+and CD8+T cells co-cultured with aAPCs. 1.Konieczny, M., Musielak, B., Kocik, J., et al.Di-bromo-based small-molecule inhibitors of the PD-1/PD-L1 immune checkpointJ. Med. Chem.63(19)11271-11285(2020)