The MIH44 monoclonal antibody specifically binds to Glucocorticoid-induced TNF-related Ligand (GITR Ligand). The GITR Ligand protein is encoded by the Tnfsf18 (Tumor necrosis factor ligand superfamily member 18) gene. The GITR Ligand is a type II transmembrane protein that is expressed on endothelial cells and antigen presenting cells, including B cells, macrophage and dendritic cells. The GITR Ligand reportedly costimulates T cell activation and reverses CD4+CD25+ Treg cell-mediated suppression by interaction with its cognate receptor, GITR that is expressed by these cells.
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.