The RPM.4 monoclonal antibody specifically recognizes CD42d (Platelet glycoprotein V, GPV). CD42d is a 88-kDa type I transmembrane glycoprotein which noncovalently associates with GPIb and GPIX to form a receptor for von Willebrand factor on megakaryocytes and resting platelets. The binding sites for von Willebrand factor and thrombin have been localized to the GPIbα chain of the GPI-b-V-IX complex. GPV is cleaved by thrombin to release a 70 kDa soluble fragment, which contains the epitope recognized by mAb RPM.4. Although the rat CD42d protein's structure is similar to that of human CD42d, the RPM.4 antibody does not cross-react with human platelets.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).