Antibody
hideAntibodies (also known as immunoglobulins, abbreviated Ig) are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are typically made of basic structural units—each with two large heavy chains and two small light chains—to form, for example, monomers with one unit, dimers with two units or pentamers with five units. Antibodies are produced by a kind of white blood cell called a plasma cell. There are several different types of antibody heavy chains, and several different kinds of antibodies, which are grouped into different isotypes based on which heavy chain they possess. Five different antibody isotypes are known in mammals, which perform different roles, and help direct the appropriate immune response for each different type of foreign object they encounter.
Although the general structure of all antibodies is very similar, a small region at the tip of the protein is extremely variable, allowing millions of antibodies with slightly different tip structures, or antigen binding sites, to exist. This region is known as the hypervariable region. Each of these variants can bind to a different target, known as an antigen. This huge diversity of antibodies allows the immune system to recognize an equally wide diversity of antigens. The unique part of the antigen recognized by an antibody is called an epitope. These epitopes bind with their antibody in a highly specific interaction, called induced fit, that allows antibodies to identify and bind only their unique antigen in the midst of the millions of different molecules that make up an organism. Recognition of an antigen by an antibody tags it for attack by other parts of the immune system. Antibodies can also neutralize targets directly by, for example, binding to a part of a pathogen that it needs to cause an infection.
The large and diverse population of antibodies is generated by random combinations of a set of gene segments that encode different antigen binding sites (or paratopes), followed by random mutations in this area of the antibody gene, which create further diversity. Antibody genes also re-organize in a process called class switching that changes the base of the heavy chain to another, creating a different isotype of the antibody that retains the antigen specific variable region. This allows a single antibody to be used by several different parts of the immune system. Production of antibodies is the main function of the humoral immune system.
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News tagged with antibodies
Researchers Build Artificial Immune System to Solve Computational Problems
Technology / Computer Sciences
Dec 03, 2009 |
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(PhysOrg.com) -- By mimicking the way that a living body acquires immunity to disease through vaccination, researchers have designed an artificial immune system to solve optimization problems more effectively ...
Vaccine being developed to help smokers quit
Medicine & Health / Medications
Nov 20, 2009 |
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(PhysOrg.com) -- Glaxo-SmithKline has joined forces with Nabi Pharmaceuticals to produce a vaccine to help smokers give up their addiction permanently.
Scientists discover promising new path for treating traumas
Oct 25, 2009 |
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(PhysOrg.com) -- A discovery by scientists at the Oklahoma Medical Research Foundation could help save lives threatened by traumatic injuries like those sustained in car crashes or on the battlefield. The ...
Scientists show why anti-HIV antibodies are ineffective at blocking infection
Medicine & Health / HIV & AIDS
Apr 22, 2009 |
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Some 25 years after the AIDS epidemic spawned a worldwide search for an effective vaccine against the human immunodeficiency virus (HIV), progress in the field seems to have effectively become stalled. The ...
A natural approach for HIV vaccine
Medicine & Health / HIV & AIDS
Mar 15, 2009 |
4 / 5 (1) |
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(PhysOrg.com) -- For 25 years, researchers have tried and failed to develop an HIV vaccine, primarily by focusing on a small number of engineered "super antibodies" to fend off the virus before it takes hold. So far, these ...
Scientists engineer new type of vaccination that provides instant immunity
Mar 02, 2009 |
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The experiments, thus far performed only in mice, appear to overcome a major drawback of vaccinations - the lag time of days, or even weeks, that it normally takes for immunity to build against a pathogen. This new method ...
Scientists identify human monoclonal antibodies effective against bird and seasonal flu viruses
Biology /
Feb 22, 2009 |
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Researchers at the Dana-Farber Cancer Institute, Burnham Institute for Medical Research and the Centers for Disease Control and Prevention have reported the identification of human monoclonal antibodies (mAb) that neutralize ...
Scientists Find First Immune Responses to HIV Infection Ineffective
Medicine & Health / HIV & AIDS
Oct 09, 2008 |
4.9 / 5 (9) |
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(PhysOrg.com) -- Scientists have identified the very first antibodies to appear in the wake of HIV infection and have concluded that they are virtually impotent in mounting a meaningful defense against the invading virus.
Tiny magnetic discs could kill cancer cells: study
Nanotechnology / Bio & Medicine
Nov 29, 2009 |
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Tiny magnetic discs just a millionth of a metre in diameter could be used to used to kill cancer cells, according to a study published on Sunday.
New cancer target for non-Hodgkin's lymphoma
Nov 22, 2009 |
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Physician-scientists from Weill Cornell Medical College have discovered a molecular mechanism that may prove to be a powerful target for the treatment of non-Hodgkin's lymphoma, a type of cancer that affects lymphocytes, ...
Scientists identify DNA that regulates antibody production
Nov 20, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- When foreign invaders trip the immune system’s alarm, antibodies need to be specially sculpted to attack them head on. New research now shows that gene segments called enhancers control the reshuffling of ...
New Synthetic Molecules Trigger Immune Response to HIV and Prostate Cancer
Nov 05, 2009 |
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(PhysOrg.com) -- Researchers at Yale University have developed synthetic molecules capable of enhancing the body’s immune response to HIV and HIV-infected cells, as well as to prostate cancer cells. Their ...
Breakthrough in fight against Hendra virus
Oct 30, 2009 |
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(PhysOrg.com) -- There has been a breakthrough in the fight against the deadly Hendra virus following the development of a treatment which shows great potential to save the lives of people who become infected ...
Scientists Propose New Explanation for Flu Virus Antigenic Drift
Oct 29, 2009 |
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(PhysOrg.com) -- Influenza viruses evade infection-fighting antibodies by constantly changing the shape of their major surface protein. This shape-shifting, called antigenic drift, is why influenza vaccines ...
Cocaine Vaccine Shows Promise for Treating Addiction
Oct 05, 2009 |
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(PhysOrg.com) -- Immunization with an experimental anti-cocaine vaccine resulted in a substantial reduction in cocaine use in 38 percent of vaccinated patients in a clinical trial supported by the National Institute on Drug ...
