The SK9 monoclonal antibody specifically recognizes CD1a. CD1a is a ~49 kDa type I transmembrane glycoprotein that associates non-covalently with β2-microglobulin. The CD1a antigen is present on 60% to 90% of thymocytes, some T-cell leukemias and lymphomas, Langerhans cells, and a subset of dendritic cells. The CD1a antibody does not react with peripheral blood T and B lymphocytes, monocytes, normal bone marrow mononuclear cells, or normal tonsillar B and T lymphocytes. The CD1a antigen has structural similarities to MHC class I antigens and plays a role in the presentation of non-peptide antigens.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).