Ultra-LEAF™ Purified anti-human VISTA (PD-1H) Antibody, VISTA, W20178L,BioLegend,607354

VISTA, V-domain Ig suppressor of T cell activation, suppresses T cell activation and was initially identified by affymetrix analysis of activated versus resting mouse CD25+CD4+natural Tregcells. Human Vista is a type I transmembrane protein with a single extracellular IgV domain. It is 311 amino acids (aa) long, contains a 32-aa signal peptide, a 130-aa extracellular IgV domain, 33-aa stalk region, 20-aa transmembrane domain, and 96-aa cytoplasmic tail. VISTA shares significant sequence homology with the B7 family ligands PD-L1 and PD-L2. VISTA is predominantly expressed in hematopoietic tissues, highly expressed in human placenta, which may be indicative of a functional role for VISTA in allofetal tolerance. Flow cytometry shows that human VISTA is expressed in subsets of CD11bhiblood monocytes, dendritic cells, about 20% of CD4, with low density in CD8 T cells, and CD66b+neutrophils at an intermediate intensity. VISTA serves both as a ligand (for antigen presenting cells) and as a receptor (for T cells). B7-H5 expressing on APCs or soluble B7-H5-Ig fusion proteins inhibit T cell proliferation and cytokine production in vitro. B7-H5 also inhibits the expression of T cell activation markers CD44 and CD69. In murine tumor models, anti-VISTA monoclonal antibodies (mAbs) prime to an increased number and elevated function of intratumoral T cells and in that way boost antitumor immunity. VISTA is negative checkpoint regulator and a promising target for cancer immunotherapy.