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 an oligonucleotide that contains an antibody clone-specific barcode (ABC) flanked by a poly-A tail on the 3' end and a PCR handle (PCR primer binding site) on the 5' end. The ABC for this antibody was designed to be used with other BD AbSeq oligonucleotides conjugated to other antibodies. All AbSeq ABC sequences were selected in silico to be unique from human and mouse genomes, have low predicted secondary structure, and have high Hamming distance within the BD AbSeq portfolio, to allow for sequencing error correction and unique mapping. The poly-A tail of the oligonucleotide allows the ABC to be captured by the BD Rhapsody™ system or other oligo-dT-based capture systems. The 5' PCR handle allows for efficient sequencing library generation for Illumina sequencing platforms.