The SY/11B5 monoclonal antibody specifically binds to CD157 which is also known as BST-1 (Bone marrow stromal antigen 1), BP-3/IF-7, Mo5, ADP-ribosyl cyclase 2, and cADPr hydrolase 2. CD157 is a 40-46 kDa glycophosphatidylinositol-linked cell membrane glycoprotein. It is an ectoenzyme that has both cyclic ADP-ribose hydrolase and ADP-ribosyl cyclase activities. CD157 is expressed as a homodimer by a variety of cell types including bone marrow stromal cells, granulocytes, monocytes, macrophages, dendritic cells, endothelial cells, and B and T cell progenitors. In addition to its ectoenzyme activities, CD157 reportedly functions as a receptor involved in neutrophil and monocyte adhesion, transendothelial migration and diapedesis and in tumor cell migration.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.