The 3D7 antibody reacts with CD131, the 120 kD common β chain (βc) which is shared with the receptor complexes for human granulocyte-macrophage colony stimulating factor (GM-CSFR), interleukin-3 (IL-3R) and interleukin-5 (IL-5R). Together with the α subunit of either the IL-3R (IL-3Rα), IL-5R (IL-5Rα), or GM- CSFR (GM-CSFRα), the common β chain forms high-affinity, signaling receptors for human IL-3, IL-5 and GM-CSF, respectively. Cell surface βc are expressed by a variety of different cell types including hematopoietic progenitor cells derived from pluripotent stem cells, monocytes, neutrophils, eosinophils, basophils, endothelial cells, fibroblasts, and Langerhans cells. The immunogen used to generate this hybridoma was cells co-transfected with expression vectors which contained cDNA for the human IL-3 α and β chains.
The antibody was conjugated to BD Horizon™ BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.