The DX12 monoclonal antibody specifically binds to human CD161 which is also known as Natural killer cell surface protein P1A (NKR-P1A). CD161 is encoded by the KLRB1 (Killer cell lectin-like receptor subfamily B member 1) gene. CD161 is a member of the C-type lectin superfamily and is also referred to as C-type lectin domain family 5 member B (CLEC5B). CD161 is a 80 kDa disulfide-linked homodimer, type II membrane glycoprotein. CD161 is expressed mostly on NK cell populations and on subsets of CD4+ and CD8+ αβ T cells, NKT cells and γδ T cells. Reports indicate that CD161 is expressed preferentially on CD45RO+ T cells, however, it can be found on a subset of thymocytes and fetal liver T cells. Its function has not been fully elucidated, but reports indicate that NKR-P1A may serve as a specific receptor for some NK cell targets. The DX12 antibody can reportedly inhibit spontaneous cytotoxicity mediated by certain NK cell clones.
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.