The IP26 monoclonal antibody specifically recognizes a monomorphic determinant on the αβ T-cell receptor (TCRαβ). The TCRαβ is a disulfide-linked 80 kDa heterodimer consisting of a 44 kDa α chain and a 37 kDa β chain. The TCRαβ is normally expressed on 50-70% of thymocytes and on a large fraction of mature T cells including greater than 95% of peripheral blood CD3+ T cells. The TCRαβ serves as a receptor for peptide antigens bound to MHC molecules. The IP26 antibody is mitogenic and useful for the flow cytometric analysis of TCRαβ+ T-cell subsets.
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.