Mouse VISTA/B7-H5/PD-1H APC-conjugated Antibody

VISTA, also known as B7-H5, PD-1H, Platelet Receptor Gi24, Dies1 (Differentiation of ESC-1), SISP1 and C10orf54, is a 55-65 kDa member of the Ig superfamily. It is a transmembrane molecule expressed in bone, on embryonic stem cells (ESCs), and on tumor cell surfaces. On ESCs, VISTA appears to positively interact with BMP4, 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. Mature mouse VISTA is a 277 amino acid (aa) type I transmembrane glycoprotein (aa 33-309). It contains a 149 aa extracellular region (aa 33-191) with one V-type Ig-like domain (aa 33-161) and a 97 aa cytoplasmic domain. Based on human VISTA, mouse Gi24 will likely undergo proteolytic cleavage by MT1-MMP, generating a soluble 30 kDa extracellular fragment, plus a 25-30 kDa membrane-bound fragment. There are two potential isoform variants. One contains a deletion of aa 127-187, while another shows an alternative start site at Met82. Over aa 33-191, mouse VISTA/Dies1 shares 78% and 70% aa sequence identity with rat and human VISTA, respectively.