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™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.