A radiobinding assay is a method of detecting and quantifying
antibodies
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that caus ...
targeted toward a specific
antigen
In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response.
...
. As such, it can be seen as the inverse of
radioimmunoassay
A radioimmunoassay (RIA) is an immunoassay that uses radioactive tracer, radiolabeled molecules in a stepwise formation of immune complexes. A RIA is a very sensitive in vitro assay technique used to measure concentrations of substances, usually m ...
, which quantifies an antigen by use of corresponding antibodies.
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Technique
The corresponding antigen is
radiolabel
A radioactive tracer, radiotracer, or radioactive label is a synthetic derivative of a natural compound in which one or more atoms have been replaced by a radionuclide (a radioactive atom). By virtue of its radioactive decay, it can be used to exp ...
ed and mixed with the fluid that may contain the antibody, such as
blood serum
Serum () is the fluid and solvent component of blood which does not play a role in clotting. It may be defined as blood plasma without the clotting factors, or as blood with all cells and clotting factors removed. Serum contains all proteins ex ...
from a person. Presence of antibodies causes precipitation of antibody-antigen complexes that can be collected by
centrifugation
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...
into pellets. The amount of antibody is proportional to the radioactivity of the pellet, as determined by
gamma counting.
[Anti-dsDNA [I-125] Radiobinding Assay Kit]
At PerkinElmer Life Sciences, Inc. Retrieved Jan 2011
Uses
It is used to detect most
autoantibodies
An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own proteins. Many autoimmune diseases (notably lupus erythematosus) are associated with such antibodies.
Pr ...
seen in
latent autoimmune diabetes.
References
Immunologic tests
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