The 4B4-1 monoclonal antibody specifically binds to CD137 which is also known as 4-1BB, and ILA (induced by lymphocyte activation). CD137 is a type I transmembrane glycoprotein that belongs to the TNF/NGF receptor family. It is encoded by TNFRSF9 (tumor necrosis factor receptor superfamily, member 9). CD137 is expressed on activated T cells, B cells, monocytes, and follicular dendritic cells. CD137 plays roles in the costimulation, differentiation and survival of T cells and B cells.
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).