The 190909 antibody specifically recognizes a common epitope on the extracellular domains of CD16 (also known as, Fc gamma RIII) and CD32 (Fc gamma RII). CD16 and CD32 serve as low affinity receptors for mouse IgG Fc constant regions and play roles in the activation or inhibition of phagocytosis, antibody-dependent cellular cytotoxicity (ADCC), degranulation, and B cell proliferation. These receptors are variably expressed on B lymphocytes, natural killer (NK) cells, monocytes, macrophages, dendritic cells, Kupffer cells, granulocytes, mast cells, immature thymocytes, and some activated mature T lymphocytes. CD16 and CD32 are single-pass type I transmembrane glycoproteins with two extracellular Ig-like domains and belong to the Ig superfamily. Ligand-bound CD16 can associate with two disulfide-linked FcR-gamma subunits (FcεRIγ) that contain cytoplasmic immunoreceptor tyrosine-based activation motifs (ITAMs) which deliver activating signals intracellularly. CD32 has an intracellular domain with an immunoreceptor tyrosine-based inhibitory motif (ITIM) and functions as an inhibitory receptor.
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.