ActiveMax® Recombinant Human IL-15 Protein, 50µg

Background
Interleukin 15 is also known as IL15, IL-15, and is a cytokine with structural similarity to IL-2. Like IL-2, IL-15 binds to and signals through the IL-2/IL-15 beta chain (CD122) and the common gamma chain (gamma-C, CD132). IL-15 is secreted by mononuclear phagocytes (and some other cells) following infection by virus(es). This cytokine induces cell proliferation of natural killer cells; cells of the innate immune system whose principal role is to kill virally infected cells. Interleukin 15 (IL-15) regulates T and natural killer (NK) cell activation and proliferation. Survival signals that maintain memory T cells in the absence of antigen are provided by IL-15. This cytokine is also implicated in NK cell development. In rodent lymphocytes, IL-15 prevents apoptosis by inducing an apoptosis inhibitor, BCL2L1/BCL-x(L). IL-15 has been shown to enhance the anti-tumor immunity of CD8+ T cells in pre-clinical models. A phase I clinical trial to evaluate the safety, dosing, and anti-tumor efficacy of IL-15 in patients with metastatic melanoma and renal cell carcinoma (kidney cancer) has begun to enroll patients at the National Institutes of Health.

Source
ActiveMax® Recombinant Human IL-15 Protein (ActiveMax® Human IL-15) Asn 49 - Ser 162 (Accession # AAH18149) was produced in human 293 cells (HEK293)

Molecular Characterization
ActiveMax® Human IL-15 contains no "tag", and has a calculated MW of 12.8 kDa. The predicted N-terminus is Asn 49. DTT-reduced Protein migrates as 13 kDa in SDS-PAGE.

Endotoxin
Less than 1.0 EU per μg of the ActiveMax® Human IL-15 by the LAL method.

Purity
>95% as determined by SDS-PAGE.

Formulation
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally Mannitol or Trehalose are added as protectants before lyophilization.

Reconstitution
See Certificate of Analysis for reconstitution instructions and specific concentrations.

Storage
Avoid repeated freeze-thaw cycles.
No activity loss was observed after storage at:
In lyophilized state for 1 year (4°C); After reconstitution under sterile conditions for 3 months (-70°C). 

Bioactivity
The bio-activity was determined by dose-dependent stimulation of the proliferation of mouse CTLL-2 cells.
The ED50 < 0.5 ng/mL, corresponding to a specific activity of >2X10⁶ Unit/mg.

 References

(1) Grabstein KH., et al., 1994, Science, 264(5161):965-8.
(2) Malamut G., et al., 2010, J Clin Invest, 120(6): 2131-43.
(3) Klebanoff CA., et al., 2004, Proc Natl Acad Sci U S A, 101(7): 1969-74.
(4) Teague RM., et al., 2006, Nat Med., 12(3): 335-41.