The UP-D1 monoclonal antibody specifically binds to Immune receptor expressed on myeloid cells 1 (IREM-1). IREM-1 is encoded by CD300LF. It is also known as CD300 antigen-like family member F (CD300f), CMRF35-like molecule 1 (CLM-1/CLM1), NK inhibitory receptor (NKIR), or Immunoglobulin superfamily member 13 (IgSF13). IREM-1/CD300f is expressed on monocytes, dendritic cells, granulocytes, and mast cells. IREM-1 is a single-pass type I transmembrane glycoprotein that belongs to the CMRF family of the Ig gene superfamily. The long intracellular region of IREM-1 contains two classical immunoreceptor tyrosine-based inhibitory motifs (ITIM). Ligand-bound IREM-1 can transduce negative regulatory signals intracellularly by recruiting SHP1 or SHIP phosphatases that in turn dephosphorylate tyrosine residues within activating cell signaling molecules. CD300f may thus play a role in regulating inflammatory responses involving myeloid cells.
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.