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™ BUV496 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 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.