BD OptiBuild™ BUV563 Mouse Anti-Human CD23

The EBVCS-5 antibody specifically binds to human CD23, the low affinity receptor for human IgE (Fc epsilon RII or FcεRII), which is also known as C-type lectin domain family 4 member J (CLEC4J). CD23 is expressed as a ~45 kDa type II membrane glycoprotein that is present at low density on most normal B lymphocytes and at higher levels on activated B lymphocytes, Epstein-Barr virus (EBV)-transformed lymphoblasts, chronic lymphocytic leukemia (CLL) cells of B-lymphocyte origin, and tonsillar B lymphocytes. CD23 expression is induced on B cells by interleukin-4 (IL-4) and is lost after isotype switching to IgA, IgG, or IgE. The CD23 antigen is not present on immature bone marrow B lymphocytes or on T lymphocytes. CD23 may also be differentially expressed on monocytes, macrophages, eosinophils, platelets, dendritic cells, and Langerhans cells. CD23 can mediate IgE-dependent cytotoxicity and phagocytosis by macrophages and eosinophils. Soluble CD23 (sCD23) can be released by CD23-positive cells as a result of proteolytic cleavage of membrane CD23. Larger fragments of sCD23 (eg, 25-37 kDa) retain their IgE-binding capacity whereas smaller fragments (ie, ≤ 12 kDa) do not. Soluble CD23 may have immunoregulatory effects on the growth and differentiation of B cells and other cell types.

The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.