The 2D9 monoclonal antibody recognizes C57BL/6 mouse Natural killer cell receptor P1D (NKR-P1D) which is also known as NKR-P1B[B6], or CD161b. CD161b is encoded by Klrb1b (killer cell lectin-like receptor subfamily B member 1B). CD161b is expressed by a functionally distinct subset of natural killer (NK) cells that express higher levels of cytotoxicity and interferon-γ (IFN-γ) than their CD161b-low or -negative counterparts. CD161b is a type II transmembrane glycoprotein that contains an immunoreceptor tyrosine-based inhibitory motif in its cytoplasmic domain. CD161b binds to C-type lectin related protein b (Clr-b) and may play a role in regulating NK cell responses. The 2D9 antibody has slight crossreactivity with cells transfected with Klrb1a/NKRP1A, Klrb1c/NKRP1C, or Klrb1f/NKRP1F.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).