B cell Activating Factor (BAFF), is a Type II member of the TNF superfamily. Although it is typically a transmembrane Protein expressed on T cells, macrophages and dendritic cells, it can also be cleaved in the extracellular region to produce a soluble form detectable in the serum. BAFF is thought to be important for the survival and matu ion of peripheral B cells. BAFF initiates signaling through three receptors with BAFF having activity on splenocytes. Recombinant BAFF is a non-glycosylated Protein containing a N terminal His tag, a thrombin cut site and 153 amino acids of the TNF-like domain. This Protein has a total molecular weight of 18.5 kDa.