The CMRF-56 monoclonal antibody specifically binds to a 96 kDa, early activation/differentiation antigen expressed on dendritic cells (DCs). The CMRF-56 antigen is expressed on isolated Langerhans cells, dermal DCs, migratory dermal DCs and monocyte derived DCs (GM-CSF, IL-4, TNF-α). Circulating blood DCs are CMRF-56-, but its expression is induced within 6 hrs of in vitro culture. Tonsil and synovial fluid DCs upregulate CMRF-56 expression following short-term in vitro culture. It is not detected on resting peripheral blood leukocytes, but is on a subpopulation of tonsil B cells and on in vitro cultured CD19+ cells. CMRF-56 was generated using the Hodgkin's-derived L428 cell line as immunogen. This reagent could be useful in flow cytometric or immunomagnetic separation procedures and immunohistochemical staining of acetone-fixed frozen tissue sections.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.