Page 1406 - Veterinary Immunology, 10th Edition

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FIG. 42.7 The antibody sandwich ELISA. Antigen is bound to the
plate by means of an antibody. The presence of that bound antigen
is detected by sequential addition of a second antibody and an
enzyme-labeled antiglobulin. Addition of the enzyme substrate
leads to a color change proportional to the amount of bound
antigen.

Another common modification of this technique is the labeled-
antigen ELISA used to detect antibodies. This is favored in
manufactured diagnostic kits. The antigen is bound to the

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