Misplaced Pages

ELISA: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 18:36, 30 September 2002 edit163.28.80.22 (talk)No edit summary← Previous edit Revision as of 03:22, 7 October 2002 edit undoAxelBoldt (talk | contribs)Administrators44,502 editsNo edit summaryNext edit →
Line 1: Line 1:
The '''Enzyme Linked Immuno-Sorbent Assay''' or '''ELISA''' is a method commonly employed in ] to detect if a certain ] is present in a given sample. The steps in this procedure are: The '''Enzyme Linked Immuno-Sorbent Assay''' or '''ELISA''' is a method commonly employed in ] to detect if a certain substance is present in a sample. It employs ] specific to the substance; these antibody are linked to an ] which produces a signal.


The steps of the general ELISA test are as follows:
⚫ # Create an ] which specifically binds to the protein of interest.
# Attach this antibody to a solid support (usually a membrane) . # Apply the sample to some sticky substrate, usually a plate with wells.
# Apply the sample to this membrane, and let the protein bind to the antibody. # Apply the enzyme-linked antibody and let it bind to the substance.
# Wash the membrane, so that only the protein bound to the antibody remains. # Wash the plate, so that unbound antibody is removed.
# Apply a second antibody which is linked to an ] and binds to the protein of interest. # Apply a chemical which is coverted by the enzyme into a fluorescent signal.
# View the result: if it fluoresces, then the sample contained the substance.
⚫ # Apply a chemical which is coverted by the enzyme into a flourescent signal.
# View the result.


The enzyme acts as an amplifier: even if only few enzyme-linked antibody are present, the enzyme molecules will produce many fluorescent signal molecules.
Any basic ] or ] textbook should have more information.

Try http://www.ncbi.nlm.nih.gov. They got books.
A variant of this techniqe is used in ] to detect if a person's ] contains antibody against a certain ] (which would indicate infection). The initial screening test for ] infection is such an ELISA test. The steps are as follows:

# Prepare a plate to which the antigen is bound
# Apply the human serum to be tested
# Wash the plate, so that unbound antibody is removed.
⚫ # Apply an enzyme-linked antibody which specifically binds to human antibody.
# Wash the plate, so that the unbound enzyme-linked antibody is removed.
⚫ # Apply a chemical which is coverted by the enzyme into a fluorescent signal.
# View the result: if it fluoresces, then the serum sample contained antibody against the antigen.

'''External links:'''
* Online bookshelf from NCBI: searchable text books in molecular biology and related fields, http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Books

Revision as of 03:22, 7 October 2002

The Enzyme Linked Immuno-Sorbent Assay or ELISA is a method commonly employed in biochemistry to detect if a certain substance is present in a sample. It employs antibody specific to the substance; these antibody are linked to an enzyme which produces a signal.

The steps of the general ELISA test are as follows:

  1. Apply the sample to some sticky substrate, usually a plate with wells.
  2. Apply the enzyme-linked antibody and let it bind to the substance.
  3. Wash the plate, so that unbound antibody is removed.
  4. Apply a chemical which is coverted by the enzyme into a fluorescent signal.
  5. View the result: if it fluoresces, then the sample contained the substance.

The enzyme acts as an amplifier: even if only few enzyme-linked antibody are present, the enzyme molecules will produce many fluorescent signal molecules.

A variant of this techniqe is used in medicine to detect if a person's blood contains antibody against a certain antigen (which would indicate infection). The initial screening test for HIV infection is such an ELISA test. The steps are as follows:

  1. Prepare a plate to which the antigen is bound
  2. Apply the human serum to be tested
  3. Wash the plate, so that unbound antibody is removed.
  4. Apply an enzyme-linked antibody which specifically binds to human antibody.
  5. Wash the plate, so that the unbound enzyme-linked antibody is removed.
  6. Apply a chemical which is coverted by the enzyme into a fluorescent signal.
  7. View the result: if it fluoresces, then the serum sample contained antibody against the antigen.

External links: