The 5B11 monoclonal antibody specifically recognizes mouse CD123, the α chain subunit (IL-3Rα) of the mouse IL-3 receptor. The IL-3Rα chain is a 60-70 kD transmembrane glycoprotein that binds IL-3 with low affinity but cannot transduce signals by itself. The mouse IL-3Rα chain can complex with either of two homologous β chain subunits (βc and βIL-3) to form high-affinity heterodimeric IL-3 receptors. The βc chain is the common β chain subunit that can complex with the α subunits of the mouse IL-3R, IL-5R and GM-CSFR to form high-affinity receptors. The βIL-3 subunit can form high affinity IL-3 receptor complexes with only the IL-3Rα subunit. The βIL-3 subunit clone is specific for mouse IL-3 and binds with low affinity. The immunogen used to generate the 5B11 hybridoma was CTLL cells transfected with the mouse IL-3R alpha chain. The 5B11 antibody does not block the binding of IL-3 protein to the high affinity IL-3 receptor heterodimer.
The antibody was conjugated to BD Horizon™ BUV395 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye has been exclusively developed by BD Biosciences to have minimal spillover into other detectors, making it an optimal choice for multicolor flow cytometry. With an Ex Max at 348 nm and an Em Max at 395 nm, BD Horizon BUV395 can be excited with a 355 nm laser and detected with a 379/28 filter.