The L138 monoclonal antibody (also known as Leu-M7) specifically binds to a glycosylated 150 kDa type II integral membrane zinc-metalloprotease. The CD13 antigen is also known as aminopeptidase N, APN, ANPEP, and gp150. The CD13 antigen is expressed on granulocytes, monocytes, mast cells, and granulocyte/macrophage progenitor cells (CFU-GM), but not on lymphocytes, platelets, or erythrocytes. It is expressed on most acute myeloid leukemia (AML) cells and some chronic myeloid leukemia (CML) cells. The CD13 antigen is also expressed on epithelial cells of the kidney, small intestine, and respiratory tract, as well as in synaptic membranes in the central nervous system (CNS). The CD13 antigen is involved in the metabolism of many regulatory peptides. Clustering of the CD13 antigen by various forms of ligation promotes the adhesion between monocytes and endothelial cells. The CD13 antigen is the receptor for human coronavirus 229E, the causative agent for some cases of upper respiratory infection.
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.