Mouse IL-2 (aka TCGF) is a 149 amino acid 15 kDa disulfide-linked monomeric glycosylate Type I cytokine [1]. IL-2 induces proliferation of a variety of lymphocytes including CD4+ and CD8+ T cells, natural killer cells, and B cells. Serum IL-2 levels are elevated in several cancers and autoimmune conditions and lymphocyte secretion is decreased in HIV patients. IL-2 binds to the IL-2R receptor which is composed of three subunits of varying affinity. The sensitive quantitative measurement of total mouse IL-2 antigen in plasma, serum, cell culture media, or other biological fluids samples is easily performed with this 96 well strip format ELISA kit. The assay measures total mouse IL-2 in the 0.01-10 ng/ml range. Samples giving mouse IL-2 levels above 10 ng/ml should be diluted in culture media or blocking buffer before use. Mouse IL-2 will bind to the capture antibody coated on the microtiter plate. After appropriate washing steps, biotinylated anti-mouse IL-2 primary antibody binds to the captured protein. Excess primary antibody is washed away and bound antibody is reacted with streptavidin conjugated to HRP. Following an additional washing step, TMB substrate is used for color development at 450nm. Color development is proportional to the concentration of IL-2 in the samples. A standard calibration curve is prepared using dilutions of purified IL-2 and is measured along with the test samples. All reagents and standards are provided in these ELISA kits.