The MHD4-46 monoclonal antibody specifically binds to Delta-Like Protein 4 which is also known as Delta4, DLL4, and DL4. Delta-Like Protein 4 is a type 1 transmembrane glycoprotein which belongs to the Delta/Serrate/Jagged Family of Notch receptor ligands. The Notch family of transmembrane receptors and their ligands play key roles in various developmental and postnatal processes by controlling cell-fate decisions. Delta-Like Protein 4 is expressed by vascular endothelial cells within certain normal tissues and tumors. It signals through Notch1 and Notch 4 Receptors and plays a critical role in vascular development and homeostasis. Delta-Like Protein 4 expression is upregulated in response to vascular endothelial growth factor (VEGF) and regulates endothelial cell proliferation during vascular sprouting. Delta-Like Protein 4 is also expressed by activated human monocytes and dendritic cells that have been stimulated with proinflammatory activators such as lipopolysaccharide. Recent evidence suggests that Delta-Like Protein 4 may contribute to the T cell potential of CD34+ cells and to the growth of various tumors, and promote tumor cell infiltration.
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.