The B-D44 monoclonal antibody specifically recognizes CD263 which is also known as, TNF-related apoptosis-inducing ligand receptor 3 (TRAIL Receptor 3/TRAIL-R3), Decoy receptor 1 (DCR1), Lymphocyte inhibitor of TRAIL (LIT), or TRID. CD263 is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that belongs to the TNF Receptor Superfamily which includes other TRAIL (CD253/APO-2 Ligand) Receptors: CD261 (TRAIL-R1), CD262 (TRAIL-R2), and CD264 (TRAIL-R4). Unlike CD261 or CD262 that contain an intracellular signaling death domain, CD263 (and CD264) lacks a cytoplasmic death domain and is unable to transduce apoptotic signals upon binding TRAIL. CD263 thus serves as a decoy receptor for TRAIL. It functions as a negative regulator of apoptotic signaling by competing with CD261 and CD262 for the binding of TRAIL. Overexpression of CD263 can reportedly attenuate TRAIL-induced apoptosis.
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).