Page 1410 - Veterinary Immunology, 10th Edition

in specific antiserum. After the membrane has been washed, an
VetBooks.ir enzyme-labeled antiglobulin solution is added. When this is

removed by washing, substrate is added, and a color develops in
the bands where the antibody has bound to antigen. When isotope-

labeled antiglobulin is used, an autoradiograph must be made and
the labeled band identified by darkening of a photographic
emulsion. Western blotting is used to identify the important
antigens in complex microorganisms or parasites (Fig. 42.11). A

variant form of the Western blot is the dot blot. Antigen solution is
filtered through a nitrocellulose membrane so that any protein
binds to the membrane. The presence of bound antigen can be
determined using specific antiserum and enzyme-labeled

antiglobulin in sequence. After exposure to enzyme substrate, the
presence of a stained dot is a positive reaction. (Use of nasal
washings as a source of the antigen, such as when trying to detect
respiratory viruses, is called a snot-blot!)

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