The AK-4 monoclonal antibody specifically binds to CD62P. CD62P is a 140 kDa type I transmembrane glycoprotein that is also known as P-Selectin, Platelet activation-dependent granule membrane protein (PADGEM), or Granule membrane protein-140 (GMP-140). CD62P is expressed by megakaryocytes, activated platelets and activated endothelium. P-Selectin is stored in the α-granules of platelets and the Weibel-Palade bodies of endothelial cells, and is rapidly transported to the plasma membrane upon activation. P-Selectin is thought to mediate the initial adhesive interactions of neutrophils and monocytes with endothelium in inflammatory responses, and of activated platelets to neutrophils and monocytes in hemostasis.
The antibody was conjugated to BD Horizon™ BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.