Cytokine that stimulates the proliferation of T-lymphocytes. Stimulation by IL-15 requires interaction of IL-15 with components of IL-2R, including IL-2R beta and probably IL-2R gamma but not IL-2R alpha. Partial recombinant protein corresponding to aa49-162 from human Interleukin-15, expressed in E. coli. Molecular Weight: ~12.9kD Biological Activity: Fully biologically active when compared to standard. The ED50 as determined by a cell proliferation assay using murine CTLL-2 cells is less than 0.5ng/ml, corresponding to a specific activity of >2.0*106IU/mg. Amino Acid Sequence: NWVNVISDLKKIEDLIQSMHIDATLYTESDVHPSCKVTAMKCFLLELQVISLESGDASIHDTVENLIILANNSLSSNGNVTESGCKECEELEEKNIKEFLQSFVHIVQMFINTS Storage and Stability: Lyophilized and reconstituted products are stable for 12 months after receipt at -20C. Reconstitute with sterile ddH2O. 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.