The 4FR6D3 monoclonal antibody specifically recognizes CD334 which is also known as Fibroblast growth factor receptor 4 (FGFR4), Tyrosine kinase related to fibroblast growth factor receptor (TKF), or JTK2. CD334 is a ~110 kDa type I transmembrane glycoprotein that belongs to the fibroblast growth factor receptor (FGFR) in the Ig superfamily (IgSF). The ligand-binding extracellular domain has three immunoglobulin-like C2-type domains followed by a transmembrane region and a cytoplasmic tail which contains a tyrosine kinase domain. CD334 serves as a high affinity receptor that dimerizes upon binding to fibroblast growth factors including FGF-1, -2, -4, -6, -8, -9, -16, -17, -18, and -19. This cell surface receptor tyrosine kinase is widely expressed on epithelial cells, fibroblasts and skeletal muscle cells and plays a role in the proliferation, differentiation, migration, and survival of these different cell types. Abnormal expression and activity of CD334 has been associated with a number of different cancers.
The antibody was conjugated to BD Horizon™ BUV496 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 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.