Description: Factor that induces terminal differentiation of late-developing B-cells to immunoglobulin secreting cells. (www.uniprot.org) Produced in E.coli. Dimeric, non-glycosylated polypeptide chain containing 113 amino acids. The ED50 as determined by the dose-dependant stimulation of the proliferation of BCL-1 cells was found to be < 0.15ng/ml.