The MEM-166 monoclonal antibody specifically binds to CD177 which is also known as NB1 (Neutrophil-specific antigen), HNA-2a (Human neutrophil alloantigen 2a), and PRV1 (Polycythemia rubra vera 1). CD177 is a glycophosphatidylinositol (GPI)-anchored plasma membrane glycoprotein (56-64 kDa). CD177 is expressed on subpopulations of neutrophils, neutrophillic metamyelocytes and myelocytes from 89 to 97% of healthy individuals. It is also expressed on secondary granules. Its expression is upregulated on granulocytes stimulated with the chemotactic peptide f-met-leu-phe (fMLP). Although the function of CD177 has not been fully established, some reports suggest its possible role as receptor molecule involved in leucocyte migration.
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.