The 7H22-E16 monoclonal antibody specifically binds to CD268, which is also known as, B cell-activating factor receptor (BAFF-R), or BAFF Receptor 3 (BR3). CD268 is a type III transmembrane protein that is likewise known as Tumor necrosis factor receptor superfamily member 13C (Tnfrsf13c). CD268/BAFF-R is a receptor for CD257 (also known as, BAFF, Blys, TALL-1, or THANK) and is expressed on B cells and a subset of activated/memory CD4+ T cells. B cells express two other BAFF receptors, CD267/TACI, or CD269/BCMA, at various times during their differentiation. CD268/BAFF-R expression starts at the transitional stage of B cell development and increases throughout B cell maturation. CD267/BAFF-R mediates most BAFF-dependent functions including B cell survival, the activation of B cell proliferation and immunoglobulin secretion, and the costimulation of T cells. Overexpression of BAFF in mice and humans is associated with autoimmunity, whereas CD268/BAFF-R deficiency may cause severe impairment in humoral responses.
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.