The UIC2 monoclonal antibody specifically binds to an extracellular epitope of CD243, which is also known as ATP-binding cassette subfamily B member 1 (ABCB1), Multidrug resistance protein 1 (MDR1), or P-glycoprotein 1. CD243 is a transmembrane glycoprotein that spans the membrane 12 times. CD243 acts as an ATP-dependent efflux pump for a large variety of lipophilic molecules and drugs. This efflux activity has been suggested to lead to resistance to the drugs used in chemotherapy. CD243 is expressed by epithelial and endothelial cells, and at low levels by T cells, B cells, NK cells, and hematopoietic stem cells. It may be expressed at high levels by multidrug resistant (MDR) tumor cells. The UIC2 antibody reportedly inhibited the efflux of CD243 substrates from MDR cells and increased the cytotoxicity of certain CD243-transported drugs. The UIC2 antibody reportedly does not crossreact with mouse CD243.
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.