Semantic resources project/Antibodies/Revised Methods/Enzyme-linked Immunosorbant Assay

Description
ELISA: Enzyme-linked Immunosorbent Assay
 * aka. EIA, or Enzyme Immunoassay

Outline
From Wikipedia: an assay used to detect the presence of an antibody or an antigen in a sample. (Emphasis added)

The key reagent appears to be an antibody "linked to" an enzyme. When the antibody binds to an antigen (which may be fixed in place as part of the preparation of the experiment), it fixes the enzyme in the same place. The enzyme can then activate a chemical reaction which makes the located antibody visible (either chromogenic or fluorogenic).

Ontology Terms
OBI: "enzyme"
 * http://purl.obofoundry.org/obo/OBI_0000427
 * OBI Browser

OBI: "ELISA"
 * http://purl.obolibrary.org/obo/OBI_0000661
 * ELISA is an assay where an enzyme linked antibody is used to detect a plate bound material in a liquid (the evaluant) utilizing a chemiluminescent reaction. The detected signal is proxy for the concentration of an analyte in the evaluant.

NCI Thesaurus: "ELISA"
 * http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#ELISA
 * A highly sensitive technique for detecting and measuring antigens or antibodies in a solution; the solution is run over a surface to which immobilized antibodies specific to the substance have been attached, and if the substance is present, it will bind to the antibody layer, and its presence is verified and visualized with an application of antibodies that have been tagged in some way. (BioTech Life Science Dictionary)

Usage
Declerck et al. "Measurement of plasminogen activator inhibitor 1 in biologic fluids with a murine monoclonal antibody-based enzyme-linked immunosorbent assay". Blood 71:1,220-225 (January 1988) "'Assuming that neutralization of t-PA is the result of a 1:1 complex formation, one would expect a ratio of 1 unit activity to 1.4 ng antigen. This would suggest that on average about two-thirds of PAI-1 antigen in plasma represent active PAI. The remaining part of the PAI-1 antigen presumably represents predominantly free but inactive PAI-1 becasue the ELISA is 12 times less sensitive to complexes between t-PA and PAI-1 than to free PAI-1.'"

Definition
OBI: ''ELISA is an assay where an enzyme linked antibody is used to detect a plate bound material in a liquid (the evaluant) utilizing a chemiluminescent reaction. The detected signal is proxy for the concentration of an analyte in the evaluant.''