The SGP1 monoclonal antibody specifically recognizes human ErbB3 (also known as HER-3), a 160-kDa glycoprotein that is a member of the epidermal growth factor receptor or ErbB family of receptor tyrosine kinases. Other members of the family include the epidermal growth factor receptor (EGFR, ErbB-1, HER1), ErbB-2 (Neu, HER2), and ErbB-4 (HER4). Members of this receptor family mediate the proliferation and differentiation of normal cells. They have a common structure consisting of an extracellular ligand-binding domain, a transmembrane region, and a cytoplasmic region that has sequence homology to tyrosine kinases, which is inactive in ErbB3. ErbB3 is expressed on neurons and in tissues from the digestive, urinary and respiratory tracts, the circulatory system, and female and male reproductive organs. It is overexpressed in a variety of tumors and is undetectable in hematopoietic tissue and cell lines derived from hematopoietic tumors. ErbB3 is able to form heterodimers with other ErbB family members that have active tyrosine kinases. This interaction is able to mediate signal transduction upon binding of ErbB3 to its ligand neuregulin, a cell adhesion molecule that is involved in development of the heart and nervous system.
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.