Reconstitute at 0.5 mg/mL in sterile PBS. BAFF is a membrane bound cytokine expressed by B cell lineage cells. The soluble form of the cytokine binds to the receptors TNFRSF13B/TACI, TNFRSF17/BCMA, and TNFRSF13C/BAFFR. BAFF is a potent B cell activator,