Upon initial thawing, recombinant mouse IL-2 (Cat. No. 550069) should be aliquoted into polypropylene microtubes and frozen at -80°C for future use.Alternatively, the product can be diluted in sterile netural buffer containing not less than 0.5 - 10 mg/mL carrier protein, such as human or bovine serum albumin, aliquoted and stored at -80°C.For use as an ELISA standard, carrier protein concentrations of 5 - 10 mg/mL are recommended.For in vtiro biological assays, carrier protein concentrations of 1 mg/mL are suggested.Failure to add carrier protein or store at the indicated temperatures may result in a loss of activity.This product should not be diluted to less than 10 µg/mL for long term storage.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: Mouse IL-2 is useful as a quantitative standard for measuring mouse IL-2 protein levels in an IL-2 specific sandwich ELISA with the purified JES6-1A12 antibody (Cat. No. 554424) as a capture antibody and the biotinylated clone JES6-5H4 (Cat. No. 554426) as the detection antibody. To obtain linear standard curves, doubling dilutions of the mouse IL-2 standard from ~2,000 to 15 pg/mL should be included with each ELISA plate.This ELISA pair is recommended primarily for measuring cytokine from experimental cell culture systems, not for assay of serum or plasma samples. For measuring IL-2 in serum or plasma, the BD OptEIA™ Mouse IL-2 Set (Cat. No. 555148) is specially formulated and recommended.

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.An activity range of 0.1 - 1.0 x 10^9 units/mg, encompassing an

ED50= 10 - 100 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.

Blocking:Recombinant mouse IL-10 (Cat. No. 550069) can be useful as a blocking control for flow cytometric analysis when used with fluorochrome conjugated antibodies, such as PE-conjugated JES-5H4 (Cat. No. 554428).Investigators are advised that the blocking application is not routinely tested for this material.Intracellular cytokine staining techniques and use of blocking controls are described in detail by C.Prussin and D.Metcalfe.