The ELISA, enzyme-linked immunosorbent assay.
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ABSTRACT: An unclassifiedMycobacterium species has been isolated from two patients with Crohn's disease (CD). Antibodies to the unclassified mycobacteria cross-reacted withMycobacterium paratuberculosis. Because of this cross-reactivity, an enzyme-linked immunosorbent assay (ELISA) was used to examine the sera of inflammatory bowel disease (IBD) patients, both CD (N=56), and ulcerative colitis (UC) (N=34), for antibodies toM. paratuberculosis, Mycobacterium kansasii, andMycobacterium tuberculosis. Controls consisted of healthy, PPD-negative individuals (N=67), and from PPD-positive patients (N=41). Eighteen resected CD patients were also examined. CD patients had a statistically significant increase in antibody titer (P=0.0003) toM. paratuberculosis compared to healthy controls. Although patients with positive PPD had elevated titers to this organism, the positive response of CD patients was not related to PPD responsiveness, area of involvement in the gut, nor to activity of the disease process.Digestive Diseases and Sciences 12/1984; 29(12):1080-1085. · 2.55 Impact Factor
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ABSTRACT: The thiazolidinedione (TZDs) class of drugs are very effective for the treatment of type 2 diabetes mellitus (T2DM). But due to the adverse effects of synthetic TZDs, their use is strictly regulated. The therapeutic actions of TZDs are mediated via modulation of peroxisome proliferator-activated receptor gamma (PPARγ). Naturally occurring PPARγ modulators are more desirable as they lack the serious adverse effects caused by TZDs. This has prompted the exploitation of medicinal plants used in traditional medicine, for their potential PPARγ activity. In the present work, we studied chebulagic acid (CHA) isolated from fruits of Terminalia chebula with respect to its effect on adipogenesis, glucose transport, and endocrine function of adipocyte. The mRNA expression profile of PPARγ target gene CCAAT/enhancer-binding protein alpha (C/EBP-α) was analyzed by qRT-PCR. The putative binding mode and the potential ligand-target interactions of CHA, with PPARγ was analyzed using docking software (Autodock and iGEMDOCKv2). The results showed that CHA enhances PPARγ signaling and adipogenesis dose dependently but in a moderate way, less than rosiglitazone. GLUT4 expression and adiponectin secretion was increased by CHA treatment. The mRNA expression of PPARγ target gene C/EBP-α was increased in CHA-treated adipocytes. The comparison of results of various parameters of adipogenesis, insulin sensitivity, endocrine function and molecular docking experiments of roziglitazone and chebulagic acid indicate that the latter behaves like partial PPARγ agonist which could be exploited for phytoceutical development against T2DM. © 2014 BioFactors, 2014.BioFactors 12/2014; · 3.09 Impact Factor
- Autoimmune Diseases, Edited by James Chan, 01/2012: chapter 10: pages 43; INTECH., ISBN: 978-953-51-0693-7
The ELISA, Enzyme-Linked Immunosorbent Assay
Featured Article: Engvall E, Perlmann P. Enzyme-
linked immunosorbent assay (ELISA). Quantitative
assay of immunoglobulin G. Immunochemistry
This paper was my first as a graduate student of
Professor Peter Perlmann at Stockholm University. At
the time, RIAs were in full bloom, but they were too
sophisticated for many areas of research and diagnosis
because they required expensive equipment and used
antigens and antibodies labeled with radioactive iso-
topes with short half-lives. We wanted something sim-
pler with the same sensitivity. Techniques for labeling
antibodies with enzymes had been described for im-
munohistochemistry (1), and we thought they could
be useful for serologic assays as well. First, we gave the
prospective enzyme immunoassay a name: enzyme-
linked immunosorbent assay, or ELISA (an important
product system, namely alkaline phosphatase. Third,
we used the procedure of a standard RIA, i.e., a com-
petitive assay in which labeled antigen competed with
antigen in the sample for binding to antibodies co-
valently coupled to cellulose particles. Separation of
repeated centrifugation and washing. We had the first
ELISA calibration curve in early 1970. As usual, it took
a while to find a journal willing to publish the result.
We were continually asked why anyone would want to
be a proof-of-concept assay. Nevertheless, most rejec-
tions stated that the paper contained nothing new.
I think the very next developments were crucial in
use the technique of coating plastic with antigens or
antibodies to make a solid phase/immunosorbent (2).
ple. It is amazing how predictably and reproducibly
one can absorb a protein onto a polystyrene surface,
and how relatively durable the absorption is. The next
development was the introduction of microtiter plates
as the assay format(3). A standardized format allowed
the subsequent development of all sorts of gadgets for
the easy execution of assays in research and diagnostic
laboratories, including multichannel pipettes, washing
came monoclonal antibodies—a match for ELISA
made in heaven, particularly for sandwich assays for
measuring antigens (4). For many years, numerous
companies have sold a wide variety of antibodies,
enzyme-labeled reagents, coated 8-well strips, and kits
to facilitate research in many areas.
in my own laboratory for all sorts of applications (5),
but I was not involved in further assay development. It
has been very rewarding to watch from the sidelines
how the ELISA has been used in numerous important
diagnostic tests and how it has created a multibillion-
dollar industry. My favorite ELISAs are the quick and
easy ones that cannot be done any other way. For ex-
performed over 7 million tests for HIV in developing
countries with an extremely simple kit (Abbott Deter-
mine), manufactured and donated by Abbott Labora-
tories. The main goal is to identify pregnant women
infected with HIV to prevent mother-to-child trans-
mission during delivery. Animal health is another area
in which the ELISA has been and still is important. A
leading diagnostic company in the area of animal dis-
eases (IDEXX Laboratories), with billions of dollars in
diseases in dogs and cats; a large portion of that is in
simple and fast ELISAs.
After all this time, it is surprising that ELISA has
the PCR, chemiluminescence, or something else. The
reason? Few assay systems are as simple as the ELISA
ment. There is beauty in simplicity.
the intellectual content of this paper and have met the following 3 re-
quirements: (a) significant contributions to the conception and design,
acquisition of data, or analysis and interpretation of data; (b) drafting
or revising the article for intellectual content; and (c) final approval of
the published article.
Authors’ Disclosures of Potential Conflicts of Interest: No authors
declared any potential conflicts of interest.
1The Burnham Institute, La Jolla, CA.
2This paper has been cited more than 2150 times since publication.
* Address correspondence to the author at: The Burnham Institute, 10901 North
Torrey Pines Rd., La Jolla, CA 92037. E-mail firstname.lastname@example.org.
Received August 31, 2009; accepted September 17, 2009.
Previously published online at DOI: 10.1373/clinchem.2009.127803
Clinical Chemistry 56:2
Role of Sponsor: The funding organizations played no role in the
of data, or preparation or approval of manuscript.
1. Avrameas S. Coupling of enzymes to proteins with glutaraldehyde. Use of the
conjugates for the detection of antigens and antibodies. Immunochemistry
2. Engvall E, Jonsson K, Perlmann P. Enzyme-linked immunosorbent assay,
ELISA. II. Quantitative assay of protein antigen, immunoglobulin G, by means
of enzyme-labeled antigen and antibody-coated tubes. Biochim Biophys Acta
3. Voller A, Huldt G, Thors C, Engvall E. New serological test for malaria
antibodies. Br Med J 1975;1:659–61.
4. Uotila M, Ruoslahti E, Engvall E. Two-site sandwich enzyme immunoassay
with monoclonal antibodies to human alpha-fetoprotein. J Immunol Methods
5. Engvall E, Ruoslahti E. Binding of soluble form of fibroblast surface protein,
fibronectin, to collagen. Int J Cancer 1977;20:1–5.
Clinical Chemistry 56:2 (2010)