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™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.