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Assay Procedure
The cytokine ELISA (Enzyme-Linked Immuno Sorbent Assay) is a specific and highly sensitive method for quantitative measure-ments of cytokines or other analytes in solutions.
A specific monoclonal antibody (mAb) able to capture the cytokine of interest is coated on a microtiterplate. A second mAb, used for detection, binds a diffe-rent epitope on the cytokine. The detection mAb is labeled with biotin, which allows subsequent binding of a Streptavidin-conju-gated enzyme. Any unbound reagents are washed away.
When substrate is added, a color reaction will develop that is proportional to the amount of cytokine bound. The concentration of cytokine is determined by comparison with a standard curve with known concentrations of cytokine.
The sensitivity of an ELISA depends mainly on the affinity of the antibodies and on the am-plification system used.
The detection limits for cytokine ELISAs are commonly in the lower picogram/ml range.
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