DIFFUSION-IN-GEL ENZYME-LINKED IMMUNOSORBENT-ASSAY (DIG-ELISA) - QUANTIFICATION OF ANTIGEN BY DIFFUSION OVER AN ANTIBODY-COATED SURFACE

  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (4) , 355-359
Abstract
The diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) was previously used for quantification of antibodies. Using bovine serum albumin as antigen and a corresponding rabbit antiserum as antibody source, the DIG-ELISA principle was used for quantification of antigen. Antibodies were immobilized on a plastic surface, over which the antigen was allowed to diffuse in an agarose gel. The antigen-antibody reaction zones were then detected by binding of an enzyme-labeled antibody directed against the antigen. The enzyme-substrate reaction, yielding a colored reaction product, was visualized in a substrate-containing gel. The density and quality of immobilized antibody on the surface was critical. Reproducible results were obtained only when antibodies purified with affinity chromatography on immobilized antigen were used. After 46 h of diffusion the diameter of the reaction zones was directly proportional to the logarithm of the antigen concentration in the range 0.4 mg/l-1 g/l. The variability of the method (coefficient of variation) was 3%.