Competitive ELISASummary: Introduction and related products for competitive ELISA assay.
Content: The competitive ELISA is used to quantify antigen using competitive method. Briefly, the free antigen and antibody are incubated to form antigen-antibody complex and then the complex are bound to antigen-coated surface in the assay plate. The unbound antibody-antigen complex is washed off before adding enzyme-linked secondary antibody against the primary antibody. The substrate is then added and the antigen concentration can then be determined by the signal strength elicited by the enzyme-substrate reaction. In this assay, the enzyme-linked secondary antibody compete with the sample antigen which is associated with the primary antibody.
Wiki definition of competitive ELISA:
1. Unlabeled antibody is incubated in the presence of its antigen.
2. These bound antibody/antigen complexes are then added to an antigen coated well.
3. The plate is washed, so that unbound antibody is removed. (The more antigen in the sample, the less antibody will be able to bind to the antigen in the well, hence "competition.")
4. The secondary antibody, specific to the primary antibody is added. This second antibody is coupled to the enzyme.
5. A substrate is added, and remaining enzymes elicit a chromogenic or fluorescent signal.
For competitive ELISA, the higher the original antigen concentration, the weaker the eventual signal.
Keywords: competitive ELISA
Last update: 2007-03-28 01:32:56 |
