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 Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.