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™ BUV737 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 737-nm. BD Horizon Brilliant BUV737 can be excited by the ultraviolet laser (355 nm) and detected with a 740/35 filter. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into channels detecting Alexa Fluor® 700-like dyes (eg, 712/20-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 BUV737 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV737 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.