The 439-9B monoclonal antibody specifically recognizes CD104, integrin β4 chain, a 205 kDa transmembrane glycoprotein, which associates with CD49f (integrin α6 chain) to form the α6/β4 (CD49f/CD104) complex. It is expressed on epithelial cells, Schwann cells, and some tumor cells. The CD49f/CD104 complex is located in the hemidesmosomes of the epidermis, suggesting its role in epidermal cell-basement membrane adhesion. The clone 439-9B was clustered as CD104 at the fifth Human Leucocyte Differentiation Antigen International Workshop. It may be used for immunoprecipitation, immunoblotting and immunohistochemistry on frozen tissue sections.
The antibody was conjugated to BD Horizon™ BUV661 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 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.