Hemagglutination Inhibition
Introduction
Hemagglutination Inhibition is a diagnostic technique that operates on a principle similar to that of the Coomb's test, except that virus agglutinates red blood cells, not antibody. The Hemagglutination Inhibition example demonstrated in this module shows antibodies binding to virus before the virus can bind to red blood cells. The result is no agglutination because the sera contains high titer, anti-virus antibodies. The negative example shows positive agglutination because no anti-virus antibodies are present to prevent the virus from agglutinating red blood cells. The red cells in the assay serve as indicator particles. This type of testing is used in the detection of antibodies to influenza, hepatitis, measles, and rubella. Potency of antibody titers can be obtained using Hemagglutination Inhibition by determining the minimum dilution of serum required to completely inhibit agglutination of red blood cells in the presence of virus. Typicllay, sera is diluted 2-fold and added to virus followed by the addition of chicken red cells. The highest dilution which inhibits agglutination is the "titer" of that serum (i.e. A titer of 640 means that the last dilution to completely inhibit agglutination of red cells was 1:640) |
Immunological Techniques
University of Arizona
douglas.lake@asu.edu
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