The AH9R7 monoclonal antibody specifically binds to the Interleukin-9 Receptor (IL-9R, IL-9Rα) also known as CD129. CD129 is a Type I transmembrane glycoprotein and a Type I Cytokine Receptor (Hemopoietin) Superfamily member. The high-affinity, signaling IL-9 Receptor complex is comprised of CD129 (IL-9 Receptor alpha chain subunit) and CD132 (common γ chain/γc). CD129 is expressed by hematopoietic progenitors, thymocytes, T cells, B cells, macrophages, eosinophils, mast cells, epithelia cells, muscle cells and neurons. IL-9 signals through the IL-9R complex (ie, through JAK, STAT and related signal pathways) to regulate the growth, proliferation, differentiation and survival of myeloid and erythroid progenitor cells, thymocytes, T cells, B cells and some tumor cells.
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.