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 BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.