B lymphocyte stimulator (BLyS), also known as B cell-activating factor (BAFF), is a cytokine that belongs to the TNF ligand superfamily and has roles in B cell survival and differentiation.1,2 It is a type II transmembrane protein with an extracellular C-terminal TNF homology domain that is cleaved from the cell surface by a furin protease and corresponds to the soluble form of BLyS, which circulates as a trimer.1,2,3 BLyS is encoded by the TNFSF13B gene in humans, expressed primarily in monocytes, macrophages, dendritic cells, and neutrophils, and can be upregulated by IFN-γ, IL-10, IFN-α, and CD40 ligand. 1,2,4 Binding of BLyS to the B cell receptors TACI, BCMA, and BAFF-R/BR3 inhibits apoptosis in, as well as increases survival and promotes differentiation of, B cells.1,2 Elevated serum levels of BLyS have been found in patients with rheumatoid arthritis, systemic lupus erythematosus (SLE), and primary Sjögren's syndrome.3 Formulations containing a monoclonal antibody against soluble BLyS have been used in the treatment of SLE.5 Cayman's Soluble BLyS/BAFF (human, recombinant) protein can be used for cell-based assay and ELISA applications. This protein is a disulfide-linked homodimer. The reduced monomer, comprised of BLyS/BAFF (amino acids 134-285) fused to human IgG1 Fc at its N-terminus, consists of 389 amino acids and has a calculated molecular weight of 43.7 kDa. As a result of glycosylation, the monomer migrates at approximately 48-55 kDa by SDS-PAGE under reducing conditions.WARNING This product is not for human or veterinary use.
