VISTA inhibitor A4 is a potent small molecule inhibitor of VISTA (V-domain Ig suppressor of T cell activation) with binding KD of 0.49 uM.
A4 (0.1-5 uM) blocks the VISTA signaling pathway in PBMCs, enhances IFN-γ release, also restores TNF-α release, enhances the killing ability of PBMCs against tumor cells.
A4 significantly activated peripheral blood mononuclear cells (PBMCs) induced the release of cytokines such as IFN-γ and enhanced the cytotoxicity of PBMCs against tumor cells.
A4 displayed potent antitumor activity and synergized with PD-L1 antibody to enhance the therapeutic effect against cancer.
