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™ BUV496 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.