The 172224 monoclonal antibody specifically recognizes CD300 antigen-like family member A (CD300a) which is also known as Myeloid-associated immunoglobulin-like receptor 1 (MAIR-1 or MAIR-I), Mast cell-derived paired immunoglobulin-like receptor 1 (Mcpir1), CMRF35-like molecule 8 (CLM-8 or Clm8), Leukocyte mono-Ig-like receptor 1 (Lmir1), or Inhibitory receptor protein 60 (IRp60). CD300a is a single-pass type I membrane protein that is encoded by the Cd300a gene which belongs to the immunoglobulin gene superfamily. The extracellular region of CD300a contains an IgV-type domain whereas its intracellular region has three ITIMs and a non-canonical ITIM. CD300a is expressed on some B cells, NK cells, macrophages, dendritic cells, neutrophils, eosinophils, and mast cells. CD300a functions as an inhibitory receptor that can downregulate the effector functions of the cells it is expressed on.
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.