![Agglutination in the blood](https://upload.wikimedia.org/wikipedia/commons/7/79/Agglutination_in_the_blood.jpg)
Agglutination is the clumping of particles. The word ''agglutination'' comes from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''
agglutinare'' (glueing to).
Agglutination is the process that occurs if an antigen is mixed with its corresponding antibody called isoagglutinin. This term is commonly used in blood grouping.
This occurs in biology in two main examples:
# The clumping of cells such as bacteria or red blood cells in the presence of an
antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
or
complement
A complement is something that completes something else.
Complement may refer specifically to:
The arts
* Complement (music), an interval that, when added to another, spans an octave
** Aggregate complementation, the separation of pitch-class ...
. The antibody or other molecule binds multiple particles and joins them, creating a large complex. This increases the efficacy of microbial elimination by
phagocytosis
Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...
as large clumps of bacteria can be eliminated in one pass, versus the elimination of single microbial antigens.
# When people are given blood transfusions of the wrong blood group, the antibodies react with the incorrectly transfused blood group and as a result, the
erythrocytes
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
clump up and stick together causing them to agglutinate. The coalescing of small particles that are suspended in a solution; these larger masses are then (usually) precipitated.
In immunohematology
Hemagglutination
Hemagglutination
Hemagglutination, or haemagglutination, is a specific form of agglutination that involves red blood cells (RBCs). It has two common uses in the laboratory: blood typing and the quantification of virus dilutions in a haemagglutination assay.
Blood ...
is the process by which
red blood cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
s agglutinate, meaning clump or clog. The agglutin involved in hemagglutination is called
hemagglutinin
In molecular biology, hemagglutinins (or ''haemagglutinin'' in British English) (from the Greek , 'blood' + Latin , 'glue') are receptor-binding membrane fusion glycoproteins produced by viruses in the ''Paramyxoviridae'' family. Hemagglutinins ar ...
. In
cross-matching
Cross-matching or crossmatching is a test performed before a blood transfusion as part of blood compatibility testing. Normally, this involves adding the recipient's blood plasma to a sample of the donor's red blood cells. If the blood is incom ...
,
donor
A donor in general is a person, organization or government which donates something voluntarily. The term is usually used to represent a form of pure altruism, but is sometimes used when the payment for a service is recognized by all parties as rep ...
red blood cells and the recipient's serum or plasma are incubated together. If agglutination occurs, this indicates that the donor and recipient blood types are
incompatible.
When a person produces
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
against their own red blood cells, as in
cold agglutinin disease
Cold agglutinin disease (CAD) is a rare disease, rare autoimmune disease characterized by the presence of high concentrations of circulating cold sensitive antibodies, usually IgM and autoantibodies that are also active at temperatures below , dir ...
and other
autoimmune
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...
conditions, the cells may agglutinate spontaneously.
This is called
autoagglutination
In hematology, red cell agglutination or autoagglutination is a phenomenon in which red blood cells clump together, forming aggregates. It is caused by the surface of the red cells being coated with antibodies. This often occurs in cold agglutini ...
and it can interfere with laboratory tests such as
blood typing
Blood compatibility testing is conducted in a medical laboratory to identify potential incompatibilities between blood group systems in blood transfusion. It is also used to diagnose and prevent some complications of pregnancy that can occur whe ...
and the
complete blood count
A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide cytometry, information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cell ...
.
Leukoagglutination
Leukoagglutination occurs when the particles involved are
white blood cell
White blood cells, also called leukocytes or leucocytes, are the cell (biology), cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and de ...
s.
An example is the PH-L form of
phytohaemagglutinin
Phytohaemagglutinin (PHA, or phytohemagglutinin) is a lectin found in plants, especially certain legumes. PHA actually consists of two closely related proteins, called leucoagglutinin (PHA-L) and PHA-E. These proteins cause blood cells to clump ...
.
In microbiology
Agglutination is commonly used as a method of identifying specific bacterial antigens and the identity of such bacteria, and therefore is an important technique in diagnosis.
History of discoveries
Two bacteriologists, Herbert Edward Durham (-1945) and
Max von Gruber
Max von Gruber (6 July 1853, in Vienna – 16 September 1927, in Berchtesgaden) was an Austrian scientist and eugenicist. As a bacteriologist he discovered specific agglutination in 1896 with his English colleague Herbert Durham (Gruber-Widal-rea ...
(1853–1927), discovered specific agglutination in 1896. The clumping became known as Gruber-Durham reaction. Gruber introduced the term agglutinin (from the Latin) for any substance that caused agglutination of cells.
French physician Fernand Widal (1862–1929) put Gruber and Durham's discovery to practical use later in 1896, using the reaction as the basis for a test for
typhoid fever
Typhoid fever, also known as typhoid, is a disease caused by '' Salmonella'' serotype Typhi bacteria. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several ...
. Widal found that blood serum from a typhoid carrier caused a culture of typhoid bacteria to clump, whereas serum from a typhoid-free person did not. This
Widal test
The Widal test, developed in 1896 and named after its inventor, Georges-Fernand Widal, is an indirect agglutination test for enteric fever or undulant fever whereby bacteria causing typhoid fever is mixed with a serum containing specific antibod ...
was the first example of serum diagnosis.
Austrian physician
Karl Landsteiner
Karl Landsteiner (; 14 June 1868 – 26 June 1943) was an Austrian-born American biologist, physician, and immunologist. He distinguished the main blood groups in 1900, having developed the modern system of classification of blood groups from ...
found another important practical application of the agglutination reaction in 1900. Landsteiner's agglutination tests and his discovery of ABO blood groups was the start of the science of
blood transfusion
Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mo ...
and
serology
Serology is the scientific study of Serum (blood), serum and other body fluids. In practice, the term usually refers to the medical diagnosis, diagnostic identification of Antibody, antibodies in the serum. Such antibodies are typically formed in r ...
which has made transfusion possible and safer.
See also
*
Agglutination-PCR Agglutination-PCR (ADAP) is an ultrasensitive solution-phase method for detecting antibodies. Antibodies bind to and agglutinate synthetic antigen– DNA conjugates, enabling ligation of the DNA strands and subsequent quantification by qPCR. Like ...
*
Blocking antibody A blocking antibody is an antibody that does not have a reaction when combined with an antigen, but prevents other antibodies from combining with that antigen. This function of blocking antibodies has had a variety of clinical and experimental uses. ...
*
Coagulation
Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism o ...
*
Immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
*
Macrophage
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cel ...
*
Mannan oligosaccharides (MOS)
References
{{DEFAULTSORT:Agglutination (Biology)
Immunologic tests
Hematology