Types of antibodies. Did not know? The immune system produces five types of antibodies, each of which has different methods of defending the body against disease and infection. We have been looking for the vaccine that is efficient in stimulating the creation of those efficient against HIV
Antibodies are specialized Y-shaped proteins produced by the immune. They help fight disease by detecting viruses, bacteria and other pathogens (disease-causing microorganisms) and working to destroy them. Harmful infectious organisms are identified as invaders due to their antigens, which are distinct molecules on their surface. Each antibody produced by your immune system binds to a specific antigen - with a suitable molecular form - and then destroys the pathogen or marks it out for other immune cells to recognize it.1
Antibodies are also known as immunoglobulins (Ig). Immuno describes immunity and globulin describes protein.2 They are produced by B cells, a specific type of white blood cell (WBC) that originates in the bone marrow.
Although there are only five main types of antibodies, each antibody can have a different binding site that corresponds to a specific antigen. In fact, your body can produce an infinite number of attachment sites to attach to antigens.
Neither CD4, Nor Antibody - Leukocyte
This is one Among the types of antibodies: Immunoglobulin G (IgG)
Immunoglobulin, G (IgG) is responsible for about 75% of all five types of antibodies in the human body. Depending on the antigen, IgG can tag a pathogen for other immune cells and proteins to recognize it, or it can promote the release of toxins to directly destroy the microorganism.
Sometimes, IgG can trigger an undesirable response in people with autoimmune diseases, in which the immune system inadvertently attacks their own cells and tissues.3
Immunoglobulin A (IgA) Another type of antibody
Immunoglobulin A (IgA) is found mainly in mucosal tissues, such as those in the mouth, vagina, and intestines, as well as in saliva, tears, and breast milk. It is responsible for 15% of all types of antibodies found in the human body, and is produced by B cells and secreted from the lamina propria, a thin layer within the mucosa tissues.
IgA is one of the body's first-line defenses against infections. It binds to pathogens to mark them for destruction and prevents them from sticking to the epithelium, which lines the body's tissues. It is not wrong to conclude that it is among the most important types of antibodies in our defensive lines
IgA is also associated with hypersensitivity reactions in people with celiac disease and several other autoimmune diseases.4
Among the types of antibodies we also have Immunoglobulin A (IgM)
Immunoglobulin M (IgM) is also one of the first antibodies recruited by the immune system to fight infection. IgM populations increase very quickly when the body is first confronted with an infectious organism, and then plummet when IgG antibodies take over. IgM is also produced by B cells and, when linked to a pathogen, stimulates the action of other antibodies and immune cells.5
In addition to activating the immune response, a subset of IgM B cells helps to "remember" a pathogen after it has been destroyed. If you are again exposed to the pathogen later, your immune system must respond more quickly due to memory B cells.6
Immunoglobulin E (IgE) Another of these five types of antibodies
Immunoglobulin E (IgE) is the type of antibody responsible for allergic response found mainly in the lungs, skin and mucous membranes. IgE is produced by B cells secreted by lymph nodes or other lymphoid tissues located near the site of the allergen (a harmless substance that induces an allergic response).
When IgE binds to an allergen, it triggers a cascade of events. Basophiles e mast cells, which are leukocyte subtypes, degranulate (open) and release Histamine, an inflammatory compound, in the bloodstream. Histamine is responsible for allergy symptoms.7
IgE also helps to protect the body against parasitic infections, including helminths (parasitic worms).8
Immunoglobulin D (IgD) is among the types of antibodies on the initial side of the immune response of our organisms
Immunoglobulin D (IgD) is important in the early stages of the immune response. Unlike other antibodies, it does not actively circulate, but binds to B cells to instigate the immune response. As a signaling antibody, IgD helps to stimulate the release of first-line IgM to fight disease and infection.
IgD is responsible for only about 0,25% of the antibodies in the human body. Despite its vital role in "kick-starting" the immune response, IgD is arguably the least known antibody, with little knowledge of how it can participate in other parts of the immune system.9
Because immunoglobulins are combined with a specific pathogen, they can be used to diagnose some diseases based on their unique structure. Antibody tests are used to detect disease-specific antibodies in a blood sample.
Antibody tests are available to diagnose (or help diagnose) a wide variety of infectious and autoimmune diseases, including:
- Celiac disease (CD)
- Cytomegalovirus (CMV)
- Epstein-Barr virus (EBV)
- H. pylori
- Lyme disease
- mycoplasma pneumonia
- Whooping cough (whooping cough)
- Primary immunodeficiency disease (PID)
- Rubella (German measles)
- Varicella-zoster virus
- Viral hepatitis
- West Nile Virus
Antibody tests do not detect the actual pathogens that cause an infection - they detect antibodies that are produced in response to the infection. A positive result means “yes”, the test has detected the antibody or antigen. A negative result means "no", while borderline results are considered inconclusive.
The Concept of Immune Window
Depending on the disease, it may take time for enough antibodies to be produced to reach detectable levels. If done too early, during the initial window period, the test can provide a false negative result.
An antibody test can confirm that an infection has occurred, such as with COVID-19 or HIV, although it cannot say when.
Sometimes, immunoglobulin levels can be used to characterize the stage of an infection. Since IgM levels generally increase before the IgG response begins, a disease-specific IgM and IgG test can help determine whether an infection has recently occurred. For example, herpes simplex is an infection for which IgM and IgG tests can help determine the timing of the infection.10
In people with allergies, IgE tests can be used to confirm that an allergic response has occurred. These tests can also be used as part of the diagnostic process to determine if your IgE levels increase when you are intentionally exposed to an allergen.
Translated by Cláudio Souza, on December 16, 2020 from the original in What Are the 5 Types of Antibodies? Written by Elizabeth Boskey, PhD. Clinically reviewed by Rochelle Collins, DO Updated on November 30, 2020
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- Schroeder HW, Cavacini L. Structure and function of immunoglobulins. J Allergy Clin Immunol. 2010; 125 (2 Supplement 2): S41-52. doi: 10.1016 / j.jaci.2009.09.046
- Vidarsson G, Dekkers G, Rispens T. IgG subclasses and allotypes: from structure to effector functions. Immunol Frontiers. 2015: 5: 520. doi: 10.3389 / fimmu.2014.00520
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- Heyman B, Shulman, MJ. Structure, function and production of immunoglobulin M (IgM). Encyclopedia Immunobiol. 2016; 2016; 1-14. doi: 10.1016 / B978-0-12-374279-7.05001-3
- Capolunghi F, Rosado MM, Sinibaldi M, Aranburu A, Carsetti R. Why do we need IgM memory B cells?. Immunol letters. 2013; 152 (2): 114-20. doi: 10.1016 / j.imlet.2013.04.007
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- Fitzsimmons CM, Falcone FH, Dunne DW. Allergen helminths, parasite specific IgE and their protective role in human immunity. Front Immunol. 2014; 5: 61. doi: 10.3389 / fimmu.2014.00061
- Edholm ES, Bengten E, Wilson M. Insights into the function of IgD. Dev Comp Immunol. 2011; 35 (12): 1309-16. doi: 10.1016 / j.dci.2011.03.002
- Liermann K, Schäfler A, Henke A, Sauerbrei A. Evaluation of commercial herpes simplex virus IgG and IgM immunoassays. Methods J Virol. April 2014; 199: 29-34. doi: 10.1016 / j.jviromet.2014.01.001