The L178 monoclonal antibody specifically binds to CD44 which is also known as Homing-associated cell adhesion molecule (H-CAM) or Phagocytic glycoprotein 1 (Pgp-1). CD44 is a single-pass type I transmembrane glycoprotein that exists in a variety of isoforms also known as variant CD44 (CD44v) or CD44R forms. CD44 is synthesized as a 37 kDa polypeptide that is converted to an 80-95 kDa form by glycosylation via N- and O-linkages, or to a 180-200 kDa form by the addition of chondroitin sulfate. It is expressed on leucocytes, erythrocytes, epithelial cells and weakly on platelets. Depending on the cell type, CD44 may participate in a variety of functions including cell adhesion, motility and cell activation.
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.