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™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.