The OX-40 antibody reacts with the 50-kDa OX-40 Antigen (CD134), also known as OX-40 Receptor, on CD4+ T lymphocytes activated in vitro and in vivo. The antigen is a member of the NGFR/TNFR superfamily, which includes low-affinity nerve growth factor receptor, TNF receptors, the Fas antigen, CD137 (4-1BB), CD27, CD30, and CD40. CD134 supplies costimulatory signals for T-cell proliferation and effector functions. While OX-40 mAb is not mitogenic, it does augment some in vitro T-cell responses. It is also reported to block binding of OX-40 Ligand to OX-40 Antigen.
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.