The 9-4D2-1E4 monoclonal antibody specifically binds to CD115 which is also known as Colony stimulating factor 1 receptor (CSF-1R) or Macrophage colony-stimulating factor 1 receptor (M-CSFR). This type I transmembrane glycoprotein is a receptor tyrosine kinase (RTK) that belongs to the Ig superfamily. It is expressed on a variety of cells including those committed to the mononuclear phagocyte lineage, such as, monocytes, macrophages, and osteoclasts. CSF-1 binds to and signals through CSF-1R homodimers which undergo tyrosine autophosphorylation and transduce downstream signaling pathways resulting in cytoskeletal reorganization and gene expression. CSF-1R activation stimulates the proliferation, differentiation, and survival of cells within the mononuclear phagocyte system. Acting through CD115, CSF-1 induces macrophage spreading and motility, and in combination with RANKL, CSF-1 drives the differentiation of mononuclear phagocytes to become osteoclasts. Interleukin-34 (IL-34) is another ligand for CD115 that can induce similar, as well as, some different biological responses by CD115-positive target cells.
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.