The VI-PL2 monoclonal antibody specifically binds to CD61. CD61 is a 105 kDa transmembrane glycoprotein that is also known as integrin β3 and platelet glycoprotein IIIa (GPIIIa or GP3A). It is expressed on platelets, megakaryocytes, osteoclasts and endothelia. Integrin β3 associates with gpIIa (CD41) to form the CD41/CD61 complex which mediates platelet adhesion and aggregation. CD61 also associates with CD51 to form the CD51/CD61 complex (vitronectin receptor). CD61 appears to bind to fibrinogen, fibronectin, vWF, vitronectin, and thrombospondin to mediate cell adhesion.
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.