Store lyophilized recombinant human IL-15 at -20°C prior to reconstitution.This material may be reconstituted using Assay Diluent (Cat. No. 555213) or an equivalent neutral buffer containing no less than 0.5 - 1 mg/mL carrier protein, such as human or bovine albumin.Reconstituted recombinant human IL-15 should be aliquoted and stored at -80°C.Failure to add carrier protein or store at indicated temperatures may result in a loss of activity.Carrier proteins should be pre-screened for possible effects in each investigator"s experimental system.Carrier proteins may have an undesired influence on experimental results due to toxicity, high endotoxin levels or possible blocking activity.

ELISA Standard:Recombinant human IL-15 (Cat. No 560254) can be useful as a quantitative standard for measuring human IL-15 protein levels using sandwich ELISA with the purified G243-935 antibody (Cat. No. 554712) as a capture antibody and biotinylated G243-886 antibody (Cat. No. 554713) as the detection antibody.To obtain linear standard curves, investigators may want to consider using doubling dilutions of recombinant human IL-15 standard from 2000 - 15 pg/mL to be included in each ELISA plate.For measuring human IL-15 in serum or plasma, investigators are highly encouraged to use BD OptEIA™ Human IL-15 ELISA Set (Cat. No. 559268).

Bioassay:Investigators are advised that the Bioassay application is not routinely tested for this material and are highly encouraged to both titrate this material and include appropriate controls in relevant experiments.Anactivity range of 1 - 4.5 x 10^8 units/mg, encompassing an

ED50= 15 - 200 pg/mL, has previously been reported using CTLL-2 indicator cells for proliferation, with a unit defined as the amount of material needed to stimulate a half-maximal response at cytokine saturation.