The M89D3 monoclonal antibody specifically recognizes CD31, which is also known as platelet endothelial cell adhesion molecule -1 (PECAM-1), a single chain, type I transmembrane protein of approximately 130-140 kDa. CD31 is a member of the immunoglobulin supergene family. Its extracellular region is composed of 574 amino acids and contains six C2-type Ig domains, and the intracellular region is composed of 118 residues. CD31 (PECAM-1) is expressed on endothelial cells, platelets, monocytes, neutrophils and NK cells. It has also been observed on subsets of T cells, but not on circulating B cells. It has been implicated in a number of cellular phenomena, including vascular wound healing, angiogenesis, and transendothelial migration of leukocytes and platelet aggregation in inflammatory responses.
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.