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 BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).