VISTA/GI24 [MD211]

V-domain Ig-containing suppressor of T cell activation (VISTA), or PD-1H, is a member of the immunoglobulin superfamily, whose extracellular domain bears homology to the B7 family ligand, particularly PD-L1. VISTA is a transmembrane protein expressed in bone, on embryonic stem cells (ESCs), and on tumor cell surfaces. On ESC s, VISTA appears to positively interact with BMP-4, potentiating BMP signaling and the transition from an undifferentiated to a differentiated state. On tumor cells, VISTA both promotes MT1-MMP expression and activity and serves as a substrate for MT1-MMP. This increases the potential for cell motility. VISTA is a negative checkpoint regulator and is expressed on myeloid cells, T-cells and human TILs (tumor infiltrating lymphocytes) on MDSCs (myeloid-derived suppressor cells) in the TME (tumor microenvironment). Studies have reported the expression of VISTA in solid tumors such as melanoma, lung, pancreas and colorectal, these studies found that VISTA may act as an important biomarker in solid tumors. In both normal and malignant tissue, VISTA is expressed abundantly in vascular endothelial cells. It is very likely both a ligand and receptor, and is a promising target for cancer immunotherapy.