The VIM15 monoclonal antibody specifically binds to CD92 which is also known as Solute carrier family 44 member 1 (SLC44A1), or Choline transporter-like protein 1 (CHTL1). CD92 is a multipass membrane glycoprotein that belongs to the choline transporter-like family. It contains a tyrosine-based inhibitory motif (ITIM) in its cytoplasmic C-terminus. CD92 appears to be involved in choline transport for cell membrane phospholipid synthesis and in regulatory cell-signaling pathways. CD92 is strongly expressed by monocytes and at lower levels by granulocytes and some dendritic cells. It is generally expressed at low levels by B cells, endothelial cells, epithelial cells, and subsets of T cells, or NK cells. The VIM15 antibody has been shown to augment lipopolysaccharide-induced IL-10 production by monocyte-derived dendritic cells (Mo-DC). When cultured with ionomycin or calcium ionophore, maturing Mo-DC showed downregulation of CD92 expression.
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.