The UP-R1 monoclonal antibody specifically recognizes CD158f which is also known as KIR2DL5. CD158f is a ~60 kDa single-pass type I transmembrane glycoprotein that belongs to the KIR (Killer cell Ig-like receptors) family within the Ig gene superfamily. CD158f is encoded by two gene paralogs, KIR2DL5A and KIR2DL5B that show greater than 99% identity in their coding sequences. CD158f molecules contain two extracellular C2-type Ig-like domains and a long cytoplasmic domain containing one canonical immunoreceptor tyrosine-based inhibitory motif (ITIM) and another atypical ITIM sequence. Although the exact ligands for CD158f have not yet been identified, the inhibitory function of UP-R1 antibody-crosslinked CD158f was shown to primarily depend upon a Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) -dependent pathway. CD158f is highly polymorphic and is expressed on subsets of NK cells and T lymphocytes by some individuals. UP-R1 recognizes cell surface CD158f encoded by the most commonly expressed allele, KIR2DL5A*001. The UP-R1 antibody has been predicted to recognize CD158f molecules encoded by other transcriptionally-active KIR2DL5 alleles, A*012 and B*00602.
The antibody was conjugated to BD Horizon BV421 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max at 421-nm, BD Horizon BV421 can be excited by the violet laser and detected in the standard Pacific Blue™ filter set (eg, 450/50-nm filter). BD Horizon BV421 conjugates are very bright, often exhibiting a 10 fold improvement in brightness compared to Pacific Blue conjugates.