BAFF (B cell-activating factor belonging to the TNF family) is a membrane protein expressed by dendritic cells, monocytes, macrophages, follicular dendritic cells, activated T cells, activated neutrophils, and malignant B cells. BAFF, also known as BLyS (B lymphocyte stimulator), is a potent B cell growth factor. Proteolytic cleavage can result in the release of a soluble trimeric BAFF which binds to the BAFF-R/BR3, BCMA and TACI. BAFF-R/BR3 is the principal receptor for B cell survival and responses induced by BAFF.Synonyms: B cell-activating factor receptor, BAFF receptor, BAFF-R, BLyS receptor 3, BR3, TNFRSF13C, Tumor necrosis factor receptor superfamily member 13C