Description
Principle of the assay: This mouse IL-2 enzyme-linked immunosorbent assay (ELISA) applies a technique called a quantitative sandwich immunoassay. The microtiter plate provided in this kit has been pre-coated with a monoclonal antibody specific for mouse IL-2. Standards or samples are then added to the appropriate microtiter plate wells and incubated. Mouse IL-2, if present, will bind and become immobilized by the antibody pre-coated on the wells. The microtiter plate wells are thoroughly washed to remove unbound mouse IL-2 and other components in the samples. A biotin-conjugated antibody preparation specific for mouse IL-2 is added to each well and incubated. The biotin labelled antibody will attach to the wells by binding to mouse IL-2 present in the standards/samples. After plate washing, other proteins, components and unattached biotin labelled antibody are removed. Then, avidin-horseradish peroxidase (HRP) conjugate is added to each well. Avidin has a very high affinity for biotin, thus, it links the tracer (HRP) sturdily to the biotin conjugated antibody. The wells are thoroughly washed to remove all unbound avidin-HRP conjugate and a TMB (3,3'5,5' tetramethyl-benzidine) substrate solution is added to each well. The enzyme (HRP) and substrate are allowed to react over a short incubation period. Only the wells that contain mouse IL-2 will exhibit a change in colour. The extent of colour change is proportional to the quantity of mouse IL-2 present in the standards/samples. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the colour change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. In order to measure the concentration of mouse IL-2 in the samples, this kit contains two calibration diluents (Calibrator Diluent I for serum/plasma testing and Calibrator Diluent II for cell culture supernatant/ urine testing). According to the testing system, the provided standard is diluted (2-fold) with the appropriate Calibrator Diluent and assayed at the same time as the samples. This allows the operator to produce a standard curve of Optical Density (O.D.) versus IL-2 concentration (pg/mL). The concentration of IL-2 in the samples is then determined by comparing the O.D. of the samples to the standard curve