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 Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.