The NAT105 monoclonal antibody specifically recognizes CD279, which is also known as Programmed cell death 1 (PD-1). CD279 is an ~55 kDa type I transmembrane glycoprotein in the CD28/CTLA-4 family within the Ig superfamily and is encoded by the Pdcd1 gene. CD279 has an extracellular region with an IgV-like domain and an intracellular region with an immunoreceptor tyrosine-based inhibitory motif (ITIM) and an immunoreceptor tyrosine-based switch motif (ITSM). CD279 is a suppressive immunoregulatory receptor expressed on CD4-CD8- thymocytes, activated T cells, B cells and myeloid cells. CD273 (also known as PD-L2 or B7-H1) and CD274 (also known as PD-L1 or B7-DC), are ligands of CD279 and members of the B7 gene family. Upon binding, CD279 inhibits T cell proliferation and cytokine secretion. CD279 may play roles in supporting self-tolerance, reducing autoimmunity, or promoting T cell exhaustion associated with certain diseases. This antibody has been reported to be suitable for immunohistochemistry.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor™ 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.