The CH-L monoclonal antibody specifically binds to CD158b proteins. These proteins are 50-58 kDa type I glycoproteins that belong to the Killer cell immunoglobulin-like receptor (KIR) family: (KIR2DL2/L3/S2). They are also known as CD158b1 (KIR2DL2; NKAT-6; p58.2), CD158b2 (KIR2DL3; NKAT-2; p58.2), or CD158j (KIR2DS2; NKAT-5; p50.2). The CD158b molecules are composed of two extracellular Ig-like domains, and a transmembrane region. CD158b1 and CD158b2 also possess long (84 or 76 amino acids, respectively) cytoplasmic tails with two immunoreceptor tyrosine-based inhibition motifs (ITIM) whereas CD158j has a short (39 amino acid) cytoplasmic tail that lacks the ITIM motif. CD158b molecules are expressed on NK cells and subsets of TCR αβ+ cells or TCR γδ+ cells. Ligand- or CH-L antibody-bound CD158b1 or CD158b2 can reportedly inhibit cytolytic NK and T cell responses to various stimuli including certain target cells expressing MHC class I ligands encoded by HLA-C alleles (Cw 1, 3, 7 and 8). CD158j reportedly can enhance some cellular cytolytic responses.
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.