The W5C5 monoclonal antibody specifically reacts with SUSD2 (sushi domain containing 2), which is expressed on mesenchymal stem cells (MSC) and on some cancers and neoplastic cell lines. It is not detected on hematopoietic cells of the peripheral blood and bone marrow. SUSD2 is a type I transmembrane protein that may interact with galectin-1 and the potential cytokine C10orf99, through which it may affect cell growth and immune responsiveness. It has a large extracellular region that contains a sushi domain (a conserved sequence that is often associated with proteins of the complement system). SUSD2 is a marker that is useful for identifying and isolating MSC from bone marrow and endometrial tissue, and those MSC may be induced to differentiate into a wide variety of cell types. Varying levels of SUSD2 expression may correlate with either suppression or enhancement of the growth of different types of neoplastic cells, presumably via a variety of direct and indirect mechanisms.
The antibody was conjugated to BD Horizon™ BUV496 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 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.