Hemagglutination
Encyclopedia
Hemagglutination, or haemagglutination, is a specific form of agglutination
that involves red blood cell
s (RBCs). It has two common uses in the laboratory: blood typing and the quantification of virus
dilutions.
that bind to the A or B blood group
in a sample of blood.
For example, if antibodies that bind the A blood group are added and agglutination occurs, the blood is either type A or type AB. To determine between type A or type AB, antibodies that bind the B group are added and if agglutination does not occur, the blood is type A.
In blood grouping the patient's serum is tested against RBCs of known blood groups and also the patient's RBCs are tested against known serum types. In this way the patient's blood group is confirmed from both RBCs and serum. A direct Coombs test
is also done on the patient's blood sample in case there are any confounding antibodies.
s.
By serially diluting a virus suspension into an assay tray (a series of wells of uniform volume) and adding a standard amount of blood cells, an estimation of the number of virus particles can be made. While less accurate than a plaque assay, it is cheaper and quicker (taking just 30 minutes).
This assay may be modified to include the addition of an antiserum. By using a standard amount of virus, a standard amount of blood cells, and serially diluting the antiserum
, one can identify the concentration of the antiserum (the greatest dilution which inhibits hemagglutination).
Agglutination (biology)
Agglutination is the clumping of particles. The word agglutination comes from the Latin agglutinare, meaning "to glue."This occurs in biology in three main examples:...
that involves red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s (RBCs). It has two common uses in the laboratory: blood typing and the quantification of virus
Virus Quantification
Virus quantification involves counting the number of viruses in a specific volume to determine the virus concentration. It is utilized in both research and development in commercial and academic laboratories as well as production situations where the quantity of virus at various steps is an...
dilutions.
Blood Typing
Blood type can be determined by using antibodiesAntibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
that bind to the A or B blood group
ABO blood group system
The ABO blood group system is the most important blood type system in human blood transfusion. The associated anti-A antibodies and anti-B antibodies are usually IgM antibodies, which are usually produced in the first years of life by sensitization to environmental substances such as food,...
in a sample of blood.
For example, if antibodies that bind the A blood group are added and agglutination occurs, the blood is either type A or type AB. To determine between type A or type AB, antibodies that bind the B group are added and if agglutination does not occur, the blood is type A.
In blood grouping the patient's serum is tested against RBCs of known blood groups and also the patient's RBCs are tested against known serum types. In this way the patient's blood group is confirmed from both RBCs and serum. A direct Coombs test
Coombs test
Coombs test refers to two clinical blood tests used in immunohematology and immunology...
is also done on the patient's blood sample in case there are any confounding antibodies.
Viral Hemagglutination Assay
Many viruses attach to molecules present on the surface of RBCs. A consequence of this is that at certain concentrations, a viral suspension may bind together (agglutinate) the RBCs, thus preventing them from settling out of suspension. Since agglutination is rarely linked to infectivity, attenuated viruses can therefore be used in assayAssay
An assay is a procedure in molecular biology for testing or measuring the activity of a drug or biochemical in an organism or organic sample. A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized...
s.
By serially diluting a virus suspension into an assay tray (a series of wells of uniform volume) and adding a standard amount of blood cells, an estimation of the number of virus particles can be made. While less accurate than a plaque assay, it is cheaper and quicker (taking just 30 minutes).
This assay may be modified to include the addition of an antiserum. By using a standard amount of virus, a standard amount of blood cells, and serially diluting the antiserum
Antiserum
Antiserum is blood serum containing polyclonal antibodies. Antiserum is used to pass on passive immunity to many diseases. Passive antibody transfusion from a previous human survivor is the only known effective treatment for Ebola infection .The most common use of antiserum in humans is as...
, one can identify the concentration of the antiserum (the greatest dilution which inhibits hemagglutination).
External links
- Hemagglutination: Presented by the University of VirginiaUniversity of VirginiaThe University of Virginia is a public research university located in Charlottesville, Virginia, United States, founded by Thomas Jefferson...