BMSpep-57 hydrochloride, a potent macrocyclic peptide, competitively inhibits PD-1/PD-L1 interaction, exhibiting an IC50 value of 7.68 nM. It binds to PD-L1 with dissociation constants (Kds) of 19 nM and 19.88 nM as determined by MST and SPR assays, respectively. This compound enhances T cell functionality by promoting IL-2 production in PBMCs[1].

In an ELISA competition assay, BMSpep-57 demonstrated up to 98.1% inhibition of PD-1/PD-L1 binding at a concentration of 300 nM, exhibiting concentration-dependent effects with an IC50 value of 7.68 nM[1]. Furthermore, BMSpep-57 significantly increased IL-2 production at concentrations of 1 μM and 500 nM in SEB-stimulated peripheral blood mononuclear cells[1]. Additionally, exposure to BMSpep-57 (0.2-10 μM for 24 hours) had no impact on the viability of Jurkat, CHO, and HepG2 cells across the tested concentrations[1].