The 30B11.1 monoclonal antibody specifically binds to Delta-like1 (Dll1) which is also known as Delta1 and DL1. Dll1 is a 90-100 kDa type 1 transmembrane protein. It is a member of the Delta/Serrate/Jagged Family of Notch ligands. Notch ligands are classified by the presence of specific structural motifs including an N-terminal Delta-Serrate-LAG-2 (DSL) domain, EGF repeats, and the DOS domain (a specialized EGF repeat). The Notch family of transmembrane receptors and their ligands control cell-fate "decisions" during the development of many organs in a wide variety of animal species. Dll1 is expressed in the paraxial mesoderm and in some cells in the nervous system in early development. In the adult, Dll1 is expressed in a variety of tissues including at high levels in the heart and at various levels by cells within lymphoid tissues. Although Dll1 does not normally appear to play a role in T cell development, Dll1 and Notch interactions are essential for marginal zone B cell development and reportedly promote the differentiation of antibody producing 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.