IFN λ1, 2, and 3 (also known as IL-29, IL-28A and IL-28B respectively) are distantly related to the IL-10 family and the interferons. All three IFN-lambdas use a distinct receptor system composed of an IFN-λR1 subunit (also called CRF2–12) and IL-10R2 subunit (also called CRF2–14). Signaling through this receptor system induces antiviral defenses similar to, but distinct from, that of type I interferons. Recombinant human IFN-λ1 is a 19.8 kDa protein containing 178 amino acid residues.
Amino Acid Sequence
Determined by its ability to activate STAT phosphorylation in an ISRE Luciferase Reporter Assay using human colon carcinoma COLO205 cells. The expected ED 50 is 0.2–0.5 ng/ml.
Endotoxin level is <0.1 ng/μg of protein (<1EU/μg).
Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.5–1.0 mg/ml. Do not vortex. This solution can be stored at 2–8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at –20°C to –80°C.