The OX-119 monoclonal antibody specifically recognizes Signal-regulatory protein gamma (SIRP-gamma or SIRPγ) which is also known as CD172g or Signal-regulatory protein beta 2 (SIRP-beta-2 or SIRPβ2). SIRPγ (CD172g) is a ~55 kDa type I transmembrane glycoprotein that is encoded by SIRPG, which belongs to the SIRPβ2 subfamily within the Ig gene superfamily. The SIRPγ (CD172g) extracellular domain contains one amino-terminal IgV-like domain and two IgC-like domains, and a short cytoplasmic region with no known motifs. It is expressed on mature thymocytes, CD4+ T-cells, CD8+ T-cells, CD56-bright natural killer (NK) cells, all activated NK cells and some B cells. SIRPγ (CD172g) binds to CD47 (integrin-associated protein/IAP) that is widely expressed on most hematopoietic cells, epithelial cells, endothelial cells, fibroblasts and many tumor cell lines. SIRPγ (CD172g) may play a regulatory role in T cell-T cell interactions and may induce apoptosis through CD47.
The antibody was conjugated to BD Horizon Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.