The 927 monoclonal antibody specifically recognizes CD317 which is also known as Bone marrow stromal antigen 2 (BST2) or Plasmacytoid Dendritic Cell Ag-1 (PDCA-1). CD317 (BST2) is a type II transmembrane glycoprotein that is encoded by Bst2. It is highly expressed on naïve plasmacytoid dendritic cells (pDC) which comprise very small populations within lymphoid and nonlymphoid tissues. pDC are characteristically early responders to viruses through Toll-like receptors (TLR), TLR7 and TLR9. Activated pDC can produce large amounts of proinflammatory cytokines including type I interferons, Interferon-alpha (IFN-α) and Interferon-beta (IFN-β), and are also known as Type I IFN producing cells (IPC). CD317 (BST2) expression can be upregulated on a variety of other cell types following stimulation with type I IFNs and IFN gamma including T cells, B cells, plasma cells, NK cells, CD8+ and CD8- dendritic cells, and cell lines. CD317 (BST2) may play a role in sorting proteins, eg, cytokines, from the Golgi apparatus and the plasma membrane.
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.