Competitive ELISA Protocols
What is competitive Elisa? A third use of ELISA is through competitive binding. The steps for this ELISA are somewhat different than the first two examples:
Unlabeled antibody is incubated in the presence of its antigen.
These bound antibody/antigen complexes are then added to an antigen coated well.
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.")
The secondary antibody, specific to the primary antibody is added. This second antibody is coupled to the enzyme.
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.
(Note that some competitive ELISA kits include enzyme-linked antigen rather than enzyme-linked antibody. The labeled antigen competes for primary antibody binding sites with your sample antigen (unlabeled). The more antigen in the sample, the less labeled antigen is retained in the well and the weaker the signal.)
ETH - Biomacromolecules - COMPETITION ELISA
Dec 13, 2005 ... COMPETITION ELISA. IPW research units ... The ELISA protocols for detection of the antibody binding to an antigen-coated microtitre plate ...
www.pharma.ethz.ch/institute_groups/biomacromolecules/protocols/compelisa
Competitive Elisa Assay
Information on the Competitive Elisa Assay - All the information you need for Competition Elisa Assay protocol and method.
www.elisaassay.com/competition-elisa-assay