- Radial immunodiffusion
Radial immunodiffusion (or Mancini method, Mancini immunodiffusion, single radial immunodiffusion assay) is an immunodiffusion technique used in immunology to determine the quantity of an antigen by measuring the diameters of circles of precipitin complexes surrounding samples of the antigen that mark the boundary between the antigen and an antibody suspended in a medium, such as an agar gel. The diameters of the circles increase with time as the antigen diffuses into the medium, reacts with the antibody, and forms insoluble precipitin complexes.
Antigen-antibody complexes are small and soluble when in antigen excess. Therefore, precipitation near the center of the circle is usually less dense than it is near the circle's outer edge, where antigen is less concentrated.
The quantity and concentration of insoluble antigen-antibody complexes at the outer edge of the circle increases with time. Therefore, the clarity and density of the outer edge increases with time.
Expansion of the circle reaches an end point and stops when antigen and antibody reach equivalence. However, the clarity and density of the outer edge may continue to increase after the circle stops expanding.
For most antigens, the area and the square of the diameter of the circle at the circle's end point are directly proportional to the quantity of antigen and are inversely proportional to the concentration of antibody. Therefore, a graph that compares the quantities or concentrations of antigen in the original samples with the areas or the squares of the diameters of the precipitin circles on linear scales will usually be a straight line when all circles have reached their end points. Circles created by small quantities of antigen reach their end points before large quantities do. Therefore, if areas or diameters of circles are measured while some, but not all, circles have stopped expanding, such a graph will be straight in the portion that contains the smaller quantities or concentrations of antigen and will be curved in the portion that contains the larger quantities or concentrations.
While circles are still expanding, a graph that compares the quantities or concentrations of the antigen on a logarithmic scale with the diameters or areas of the circles on a linear scale may be a straight line. However, circles of the precipitate are smaller and less distinct during expansion than they are after expansion has ended. Further, temperature affects the rate of expansion, but does not affect the size of a circle at its end point. In addition, the range of circle diameters for the same quantities or concentrations of antigen is smaller while some circles are enlarging than they are after all circles have reached their end points. Therefore, measurements of the sizes of circles and of graphs produced from such measurements are often less accurate when circles are expanding than they are after expansion has ended. For that reason, it is often more desirable to take measurements after all circles have reached their end points than it is to take measurements while some or all circles are still expanding.
Measurements of large circles are more accurate than are those of small circles. It is therefore often desirable to adjust the concentration of antibody and the quantity of antigen to assure that precipitin rings will be large.
- Berne, Bernard H (1974). "Differing methodology and equations used in quantitating immunoglobulins by radial immunodiffusion — a comparative evaluation of reported and commercial techniques". Clinical Chemistry (U.S.A.: American Association For Clinical Chemistry) 20 (1): 61–69. PMID 4203461. http://www.clinchem.org/cgi/reprint/20/1/61. Retrieved 2010-05-12.
- Fahey, John L; McKelvey, Eugene M (1965). "Quantitative determination of serum immunoglobulins in antibody–agar plates". Journal of Immunology (U.S.A.: The Williams & Wilkins Co.) 94 (1): 84–90. PMID 14253527. http://www.jimmunol.org/cgi/reprint/94/1/84.pdf. Retrieved 2010-05-12.
- Mancini, G; Carbonara, AO; Heremans, JF (1965). "Immunochemical quantitation of antigens by single radial immunodiffusion". Immunochemistry (Great Britain: Pergamon Press) 2 (3): 235–254. doi:10.1016/0019-2791(65)90004-2. PMID 4956917. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B73FY-4840HKH-5B-1&_cdi=11511&_user=861681&_pii=0019279165900042&_orig=search&_coverDate=09%2F30%2F1965&_sk=999979996&view=c&wchp=dGLzVtb-zSkzk&md5=adb26ac6241a8c5df5bb523fb3529ec0&ie=/sdarticle.pdf. Retrieved 2010-05-12.
- Mancini, Giuliana (1992-06-29). "This Week's Citation Classic: Refining the Angelotron". Current Contents (ISI) 35 (26). http://www.garfield.library.upenn.edu/classics1992/A1992HX83800002.pdf. Retrieved 2010-05-12.
- A method of radial immunodiffusion where circles are measured before all reach their end points in website of Louisiana State University School of Medicine, New Orleans, LA.
Medical test: Immunologic techniques and tests (CPT 86000-86849) Immunologic techniques
and tests ·
Wikimedia Foundation. 2010.
Look at other dictionaries:
radial immunodiffusion — (RID) a quantitative immunodiffusion technique in which the antigen solutions are placed in wells cut in an agar plate containing antiserum; the area or diameter of the precipitin ring around an unknown solution is compared with the rings of a… … Medical dictionary
single radial immunodiffusion — (RID) assay An immunodiffusion technique that quantitates antigens by following their diffusion through a gel containing antibodies directed against the test antigens … Dictionary of microbiology
immunodiffusion — A technique to study antigen antibody reactions by observing precipitates formed by antigen antibody complexes, which are formed by combination of specific antigen and antibodies which have diffused in a gel in which they have been separately… … Medical dictionary
single radial diffusion — radial immunodiffusion … Medical dictionary
Ouchterlony double immunodiffusion — Picture of an Ouchterlony double immunodiffusion plate, after immunodiffusion has taken place. In this, titre value of an antigen is quantified. The central well has an antibody, and the surrounding wells have decreasing concentration of the… … Wikipedia
RID — • radial immunodiffusion; • reduced interference distribution; • remission inducing drug; • ruptured intervertebral disc … Dictionary of medical acronyms & abbreviations
RID — Abbreviation for radial immunodiffusion. * * * radial immunodiffusion; reduced interference distribution; remission inducing drug; ruptured intervertebral disc * * * radial immunodiffusion … Medical dictionary
C-reactive protein — C reactive protein, pentraxin related Constructed from 1B09 … Wikipedia
Counterimmunoelectrophoresis — A laboratory technique used to evaluate the binding of an antibody to its antigen. Counterimmunoelectrophoresis is similar to immunodiffusion, but with the addition of an applied electrical field across the diffusion medium, usually an agar or… … Wikipedia
Coombs test — Diagnostics MeSH D003298 Coombs test (also known as Coombs test, antiglobulin test or AGT) refers to two clinical blood tests used in immunohematology and immunology. The t … Wikipedia