The 15D3 monoclonal antibody specifically recognizes P-glycoprotein which is also known as CD243, ATP-binding cassette subfamily B member 1 (ABCB1) or Multidrug resistance protein 1 (MDR1). P-glycoprotein is a ~170 kDa transmembrane glycoprotein protein that spans the membrane 12 times. P-glycoprotein acts as an ATP-dependent efflux pump for a large variety of drugs. It may be expressed at high levels by multidrug resistant (MDR) tumor cells. This efflux activity may lead to cellular resistance to the drugs used in chemotherapy. P-glycoprotein is present in many normal cell types including endothelial, epithelial, or secretory cells, and might protect them from naturally occurring xenobiotics.
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.