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™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.