Agglutination is the clumping of particles. The word agglutination comes from the Latin agglutinare (glueing to).
Agglutination is a reaction in which particles (as red blood cells or bacteria) suspended in a liquid collect into clumps usually as a response to a specific antibody.
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 or complement. The antibody or other molecule binds multiple particles and joins them, creating a large complex. This increases the efficacy of microbial elimination by phagocytosis 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 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.
YouTube Encyclopedic
-
1/3Views:56 2623 013427
-
Latex Agglutination Test - Amrita University
-
Slide agglutination test short video
-
Agglutination and Precipitation by Dr. Mamoona
Transcription
LATEX AGGLUTINATION TEST The latex agglutination test is a laboratory method to check for certain antibodies or antigens in clinical laboratories for the detection of infectious diseases such as rheumatoid arthritis, hepatitis B, haemophilus influenza, enisseria meningitidism, etc. In 1956 Singer and Plotz first described the Rheumatoid Factor Test, a test based on latex agglutination. In rheumatoid arthritis IgG antibodies produced by lymphocytes in the synovial joint react with the IgM antibodies (RF, rheumatoid factor) to generate immune complexes that activate the complement and cause the tissue destruction. The reaction between a particulate antigen and an antibody results in visible clumping called agglutination. Antibodies that produce such reactions are known as agglutinins. The principle of agglutination reactions are similar to precipitation reactions: they depend on the cross linking of polyvalent antigens. When the antigen is an erythrocyte, it is called hemagglutination. Theoretically, all antibodies can agglutinate particulate antigens but IgM, due to its high specificity, is a particularly good agglutinin. Agglutination tests employ latex particles, gelatin beads, colloidal particles, or preserved mammalian or avian blood cells to facilitate visualization of agglutination. In the latex agglutination test, the sample to be tested is sent to the lab where it mixed with latex beads coated with a specific antigen or antibody. Materials Required: 1.5 ml Vials. Microcentrifuge. Pipette. Micro tips. Laboratory refrigerator. Glycine saline buffer. Blocking buffer. Antigen for coating. Latex beads. Test antiserum. Glass slides. Beaker. Toothpick. Procedure: Coating of Latex To 20 µl of latex beads taken in a 1.5 ml vial, add 40 µl of glycine-saline buffer. Add 60 µl of antigen to the latex and incubate at 37oC for 2 hours. Spin down at 5000 rpm for 10 minutes and carefully aspirate the supernatant. Resuspend the pellet in 1 ml of blocking buffer and spin down at 5000 rpm for 10 minutes. Repeat the washing once more. Add 90 µl of blocking buffer to the pellet, mix well. Incubate at 40C, overnight. Agglutination Test: To 200 µl of glycine-saline buffer taken in a vial, add 4 µl of test antiserum (50 times diluted). Add 50 µl of antigen to 50 µl of diluted antiserum in a 1.5 ml vial, mix well and incubate at room temperature for 10 minutes. Pipette 10 µl of coated latex on a glass slides. Add 10 µl of diluted test antiserum to slide A. Add 10 µl of antiserum mixed with antigen (from step 8) to B. Add 10 µl of glycine-saline buffer to C. Take a toothpick and mix the contents on each slide. Discard the toothpick after using it for one slide and use a new one for the next slide. After mixing, wait for 2 minutes to observe the result. Result: The clumping of latex beads (agglutination) indicates the presence of suspected particles. Absence of white clumps indicates a negative result, i.e., the suspected particle is not present. ADVANTAGES: Helps in detecting certain antigens or antibodies in a variety of bodily fluids such as blood, saliva, urine or cerebrospinal fluid. Ability to obtain semi-quantitative results. A low individual test cost. Relatively short time to obtain results.
In immunohematology
Hemagglutination
Hemagglutination is the process by which red blood cells agglutinate, meaning clump or clog. The agglutin involved in hemagglutination is called hemagglutinin. In cross-matching, donor 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 against their own red blood cells, as in cold agglutinin disease and other autoimmune conditions, the cells may agglutinate spontaneously.[1] This is called autoagglutination and it can interfere with laboratory tests such as blood typing and the complete blood count.[2][3]
Leukoagglutination
Leukoagglutination occurs when the particles involved are white blood cells.
An example is the PH-L form of phytohaemagglutinin.
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 (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. 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 was the first example of serum diagnosis.
Austrian physician Karl Landsteiner 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 and serology which has made transfusion possible and safer.
See also
- Agglutination-PCR
- Blocking antibody
- Coagulation
- Immune system
- Macrophage
- Mannan oligosaccharides (MOS)
References
- ^ Quist, Erin; Koepsell, Scott (2015). "Autoimmune Hemolytic Anemia and Red Blood Cell Autoantibodies". Archives of Pathology & Laboratory Medicine. 139 (11): 1455–8. doi:10.5858/arpa.2014-0337-RS. PMID 26516943.
- ^ Denise M Harmening (30 November 2018). Modern Blood Banking & Transfusion Practices. F.A. Davis. p. 141. ISBN 978-0-8036-9462-0.
- ^ Bain, BJ; Bates, I; Laffan, MA (2017). Dacie and Lewis Practical Haematology (12 ed.). Elsevier Health Sciences. pp. 32–3. ISBN 978-0-7020-6925-3.
| Authority control databases: National |
|---|
This page was last edited on 10 January 2024, at 14:24