Factor that induces terminal differentiation of late-developing B-cells to immunoglobulin secreting cells. Biological Activity: Fully biologically active when compared to standard. The ED50 as determined by a cell proliferation assay using human TF-1 cells is less than 0.1ng/ml, corresponding to a specific activity of > 1.0x10e7 IU/mg. Sequence: MIPTEIPTSA LVKETLALLS THRTLLIANE TLRIPVPVHK NHQLCTEEIF QGIGTLESQT VQGGTVERLF KNLSLIKKYI DGQKKKCGEE RRRVNQFLDY LQEFLGVMNT EWIIES Molecular Weight: 26.5kD PubMed ID: 3024129, 2824500, 3498940, 2823259, 15489334, 2361960, 2037074, 8483502, 22153509 Gene Name: IL5 Swiss Prot: P05113 Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.