The ik-1 monoclonal antibody specifically binds to OX40 Ligand (OX40L) which is also known as CD252 and CD134 Ligand. OX40L is encoded by TNFSF4 (Tumor necrosis factor (ligand) superfamily, member 4). OX40L a 34 kDa type II transmembrane glycoprotein that is expressed by dendritic cells, B cells, human umbilical vein endothelial cells (HUVEC) and other types of vascular endothelial cells. OX40L serves as a costimulatory ligand by binding to and signaling through OX40 (CD134) which is expressed on activated T cells. It also mediates adhesion of activated T cells or OX40-positive transformed cells to vascular endothelial cells. Monocyte-derived dendritic cells (MoDC) express OX40 Ligand after stimulation through CD40. Ligation of OX40 Ligand expressed by activated MoDC can significantly increase their cytokine production.
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.