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™ BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.