The TU169 monoclonal antibody specifically binds to the human Major Histocompatibility Complex (MHC) Class II HLA-DQ1 and DQ2 antigens and weakly to HLA-DQ3. HLA-DQ antigens exits as heterodimers comprised of polymorphic transmembrane HLA-DQ alpha and beta glycoproteins. HLA-DQ is expressed primarily on B cells, monocytes, macrophages, dendritic cells and activated T lymphocytes. HLA-DQ is involved in presenting peptidic antigens to CD4+ T lymphocytes. This antibody does not cross-react with HLA-DR2 and HLA-DR7. This antibody fixes complement.
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.