Protein. The extracellular domain of mouse VISTA aa 33-191 is fused at the C-terminus to the domain of the mouse cartilage oligomeric matrix protein COMP aa 28-72 and a His Tag. Source HEK 293 cells. Endotoxin content <0.01EU/µg purified protein LAL test Lonza. Lyophilized. Contains PBS. Purity >95% SDS-PAGE. Mouse VISTA is a 55 to 65kDa type I Ig membrane protein with the extracellular domain homologous to PD-L1. VISTA is mainly expressed on hematopoietic tissues spleen, thymus and bone marrow and on myeloid cells with lower expression on CD4 and CD8 T cells. VISTA is a new negative checkpoint regulator that potently suppresses T cell activation. Overexpression of VISTA on tumors inhibits the protective anti-tumor immunity and blockade of VISTA enhances antitumor immunity in multiple tumor models. VISTA on APC delivers negative signaling to T cells via a yet-to-identify binding partner on T cells.