CD257 (BAFF, BLyS)

Alias: BAFF, BLyS, Tumor necrosis factor ligand superfamily member 13B

BAFF (B cell activating factor belonging to the TNF family) is a TNF family member. BAFF/BLyS is a B lymphocyte stimulatory molecule that induces B cell proliferation and immunoglobulin secretion. Like APRIL, it is heterotrimeric transmembrane protein that is proteolytically processed to produce a soluble cytokine. BAFF contains a cytoplasmic domain, transmembrane domain and extracellular domain that is cleaved to produce the soluble form detectable in serum. Both BAFF and APRIL bind to the receptors BCMA and TACI, while only BAFF binds to the BAFF Receptor (BAFFR). Both BAFF and APRIL are upregulated by type I interferons, IFNγ, IL-10, G-CSF, and certain TLRs. BAFF functions as a key regulator of B-cell homeostasis and increased levels of BAFF in human sera have been found in primary biliary cirrhosis, autoimmune diabetes, rheumatic diseases, and Sjogren’s syndrome.