Description: Recombinant human BAFF (B-cell activating factor), also referred to as BlyS, is a type II transmembrane protein of the TNF superfamily. BAFF is found on T cells, macrophages and dendritic cells. BAFF contains a cytoplasmic domain, transmembrane domain and extracellular domain which can be cleaved between amino acid 133 and 134 to produce a soluble form detectable in serum. Receptors for BAFF include TACI, BAMBI and BAFFR. BAFF/BLyS is a B lymphocyte stimulatory molecule; it induces B cell proliferation and immunoglobulin secretion. In addition BAFF can provide a co-stimulation signal to T lymphocytes. Elevated levels of BAFF has been implicated in the pathogenesis of some autoimmune diseases (particularly) B cell diseases such as systemic lupus erythaematosus. Human and mouse BAFF share 86% amino acid sequence identity.