The human B cell activating factor (BAFF) and APRIL(a proliferation inducing ligand) are both type II molecules belonging to the TNF superfamily (TNFSFL 13b and 13 respectively). They are expressed by non-B cells, and are down regulated by mitogenic stimulation(2). BAFF and APRIL bind to at least two receptors: TACI (transmembrane activator and CAML-interactor) and BCMA (B cell maturation antigen), both of which are restricted to B cells (3,4). Ligation of these receptors with recombinant BAFF dramatically increases IgM production by peripheral blood B cells(1). Recently a third receptor for BAFF (BAFF-R) was described(5). BAFF and BAFFR knockout mice have a reduced numbers of mature B cells in the periphery, however TACI and BCMA knockouts do not share this phenotype, suggesting that BAFF-R may the primary receptor for BAFF in mice (8,9,10). Cell surface BAFF can be proteolytically cleaved to form a soluble trimeric molecule (2). Levels of soluble BAFF correspond with levels of autoantibodies in Sjogrens Syndrome(11). Recombinant BAFF(trn)-muCD8 binds to human cell surface TACI/BCMA/BAFFR. Functional Application: Human BAFF(trn)-muCD8 binds to human cell surface TACI/BCMA/BAFFR . Human BAFFtrn (TALL-1, Blys, THANK)-muCD8 Fusion Protein* Molecular Structure: A soluble molecule consisting of 151 (VQGPEET...c-term) aminoacids of the extracellular domain of human BAFF fused to the extracellular domain (167aa) of murine CD8 alpha, with a predicted monomeric weight of 38.5kD. A portion of the extracellular region of BAFF was truncated to eliminate a potential protease cleavage site. Transfectant Cell Line: CHO Applications: Suitable for use in Flow Cytometry and ELISA. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4C for short-term only. For long-term storage, store at -20C. Aliquots are stable for at least 6 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
