The DX27 monoclonal antibody specifically recognizes CD158b1 (KIRDL2/NKAT6), CD158b2 (KIRDL3/NKAT2), and CD158j (KIR2DS2/NKAT5) which are members of the Killer immunoglobulin-like receptor (KIR) family within the Ig superfamily. CD158b1 and CD158j contain two (KIR2D) Ig-like extacellular domains whereas CD158b2 contains three (KIR3D) Ig-like domains. These polymorphic CD158 molecules are expressed on natural killer (NK) cells and a subset of T cells and can recognize MHC class I molecules on target cells. They serve as either inhibitory receptors (CD158b1, CD158b2) that express immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in their cytoplasmic domains or activating receptors (CD158j) that lack ITIMs.
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.