The T45-2342 monoclonal antibody recognizes the mouse F4/80 antigen which is also known as EGF-like module-containing mucin-like hormone receptor-like 1 (EMR1). F4/80 is a 160 kDa glycoprotein that belongs to the EGF-TM7 family of seven-transmembrane spanning cell surface molecules. It is expressed on the surface of granulocytes and a wide range of mature tissue macrophages including, Kupffer cells, splenic red pulp macrophages, microglia, gut lamina propria macrophages, and Langerhans cells. F4/80 expression has also been reported on subpopulations of dendritic cells. F4/80 expression is heterogeneous and may be increased during inflammatory responses as observed in various mouse models of colitis, diabetes and brain injury.
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.