The ITEM-4 monoclonal antibody specifically binds to the TWEAK Receptor (TWEAK-R/TWEAKR), which is also known as CD266, or Fibroblast growth factor inducible 14 (FGF-inducible 14, FN14). The TWEAK Receptor is a ~14 kDa type I transmembrane protein that is the 12A family member of the tumor necrosis factor receptor superfamily (TNFRSF12A). It is expressed at low levels in a variety of tissues including, heart, placenta, lung, muscle, and pancreas. TWEAK Receptors are relatively highly expressed on HUVEC cells and certain tumor cell lines. TWEAK-induced TWEAK Receptor-mediated signaling can play roles in inflammation, the induction of apoptosis in certain cell types, the proliferation and migration of endothelial cells, and can promote angiogenesis within healthy and diseased tissues, eg, tumors. The ITEM-4 antibody can induce the death of certain TWEAK-sensitive tumor target cell lines. The TWEAK Receptor binds TWEAK (CD255) and can signal intracellularly by interactions with TRAF1, 2, and 3 cytoplasmic proteins leading to NF-κB activation. The ITEM-4 antibody reportedly crossreacts strongly with mouse CD266 as demonstrated by flow cytometric analysis and functional assays.
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.