The 9F5 monoclonal antibody specifically binds to CD123. CD123 is the 70 kDa IL-3 receptor α chain (IL-3Rα) that associates with the 120-140 kDa β subunit (CD131/Common β-chain/βc) to form the functional IL-3 receptor complex. The βc chain is also shared with distinct α chain subunits to form the functional heterodimeric receptors for interleukins IL-5 and GM-CSF. IL-3Rα is expressed on a subset of peripheral blood dendritic cells, myeloid precursors, basophils, mast cells, macrophages, and megakaryocytes. Reports indicate that IL-3Rα is also expressed on lymphocytes. The IL-3R plays an important role in hematopoietic progenitor cell growth and differentiation. This antibody does not block binding of IL-3 to the IL-3 receptor.
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).