The RUU-PL7F12 monoclonal antibody specifically recognizes CD61, a 110 kDa type I transmembrane glycoprotein, also known as Glycoprotein IIIa (gpIIIa), the common β-subunit (integrin β3-chain) of the gpIIb/IIIa complex and the vitronectin receptor (VNR). The gpIIb/IIIa complex and the VNR are integrins, ie, α/β-heterodimeric glycoprotein complexes that are involved in cell adhesion. With the CD41 antigen (gpIIb or αIIb), the CD61 antigen forms the gpIIb/IIIa complex, which acts as a receptor for fibrinogen, von Willebrand factor (vWf), fibronectin, and vitronectin on activated platelets. With the CD51 antigen (VNR α-chain or αv), the CD61 antigen forms the VNR, which mediates activation-independent cell adhesion to vitronectin, vWf, fibrinogen, and thrombospondin. The CD61 antigen is found on all normal resting and activated platelets. Platelets from individuals with Glanzmann's thrombasthenia show a >90% reduction of binding of CD61, and heterozygote carriers of the disorder show approximately 50% reduction. The CD61 antigen is also found on endothelial cells, megakaryocytes, and on some myeloid, erythroid, and T-lymphoid leukemic cell lines.
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.