The p44-8 monoclonal antibody specifically binds to the natural killer (NK) cell receptor, NKp44, which is also known as CD336, Natural cytotoxicity triggering receptor 2 (NCR2), or Lymphocyte antigen 95 homolog (Ly95). NKp44 is a ~44 kDa type I transmembrane protein that belongs to the natural cytotoxicity receptor (NCR) family within the immunoglobulin superfamily. NKp44 is expressed by activated NK cells. NKp44 serves as an activating receptor that can enhance NK cell mediated lysis of target cells including tumor cells and virus-infected cells. Killer activating receptor associated protein (KARAP), which is also known as DAP12, is an intracellular adaptor protein that can associate with the intracellular region of NKp44. DAP12 can then function to help transmit activating signals through its immunoreceptor tyrosine-based activation motif (ITAM).
The antibody was conjugated to BD Horizon™ BUV737 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 737-nm. BD Horizon Brilliant BUV737 can be excited by the ultraviolet laser (355 nm) and detected with a 740/35 filter. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into channels detecting Alexa Fluor® 700-like dyes (eg, 712/20-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 BUV737 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV737 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.