The JS-81 monoclonal antibody specifically binds to CD81, which is also known as, Target of the antiproliferative antibody 1 (TAPA1, TAPA-1), or Tetraspanin-28 (Tspan-28/TSPAN28). CD81 is an ~26 kDa transmembrane protein that belongs to the tetraspanin (TM4SF) family. It is involved in cell growth and signal transduction. CD81 has a very broad cellular distribution, being expressed on cells of hematopoietic, neuroectodermal and mesenchymal origin. In hematopoietic cells, the CD81 antigen is expressed on B and T lymphocytes, NK cells, thymocytes, eosinophils, germinal center follicular dendritic cells, and to a variable extent on monocytes. The CD81 antigen is not expressed on neutrophils, platelets, or erythrocytes. CD81-specific antibodies have been shown to have anti-proliferative effects on different lymphoid cell lines, particularly those derived from large cell lymphomas. They are also reported to induce homotypic cell aggregation. Immunoprecipitation studies reveal that CD81 is a component of a multimolecular complex of CD19, CD21, and CD225 that is involved in the activation and control of B cell growth.
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).