Tags: ELISA, antibody
Tags: ELISA, antibody
Detection Methods of ELISA
The ELISA (abbreviation of enzyme-linked
immunosorbent assay) is a test that uses antibodies and color change to
identify a substance.
ELISA is a popular format of "wet-lab" type analytic biochemistry assay that uses a solid-phase enzyme immunoassay (EIA) to detect the presence of a
substance, usually an antigen, in
a liquid sample or wet sample.
ELISA has three
First, direct ELISA. A major
disadvantage of the direct ELISA is the method of antigen immobilization is not
specific. The sandwich or indirect ELISA , which
is the second detection method, provides a solution to this problem, by using a
"capture" antibody specific for the test antigen to pull it out of
the serum’s molecular mixture. The use and meaning of the names "direct
ELISA" and "indirect ELISA" differs in the literature and on web
sites depending on the context of the experiment. When the presence of an
antigen is analyzed, the name "direct ELISA" refers to an ELISA in
which only a labeled primary antibody is used, and the term "indirect
ELISA" refers to an ELISA in which the antigen is bound by the primary
antibody which then is detected by a labeled secondary antibody. In the latter
case a sandwich ELISA is clearly distinct from an indirect ELISA.
Besides that, Sandwich ELISA by using an enzyme-linked
antibody that binds the Fc region of other antibodies, this can be used in a
variety of situations. Without the first layer of "capture" antibody,
any proteins in the sample may competitively adsorb to the plate surface,
lowering the quantity of antigen immobilized.
The third detection method is Competitive ELISA. Some competitive ELISA kits
include enzyme-linked antigen rather than enzyme-linked antibody. The labeled
antigen competes for primary antibody binding sites with the sample antigen
(unlabeled). The less antigen in the sample, the more labeled antigen is
retained in the well and the stronger the signal.
the ELISA can be performed to evaluate either the presence of antigen or the
presence of antibody in a sample, it is a useful tool for determining serum antibody
concentrations. It has also found applications in the food industry in detecting potential food allergens, such as milk, peanuts, walnuts, almonds, and eggs and as
serological blood test for coeliac
disease. ELISA can also be used in toxicology as a
rapid presumptive screen for certain classes of drugs.
Because of its importance, many
companies devote themselves to produce products by ELISA. For example, Creative
Peptides, they apply themselves to produce Histone Peptide ELISA, which are94
human histone peptides (H2A, H2B,
H3, H4) carrying post-translational modifications (PTMs) immobilized in an
ELISA plate. If you want to know more about ELISA, please contact us: