The 17F9 monoclonal antibody specifically binds to the 170-180 kDa transmembrane glycoprotein (P-glycoprotein), a product of the multidrug resistance-1 (MDR1) gene. This glycoprotein is expressed on MDR positive cells and has been reported to be expressed on many normal tissues, such as adrenal glands and endothelium, in the brain and skin. P-glycoprotein is known to impart drug resistance to cells by pumping many anti-cancer drugs out of the cytoplasm. 17F9 antibody is able to partially block the binding of UIC2 antibody (another MDR-specific monoclonal antibody).
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.