Medical research

Rheumatoid arthritic pain could be caused by antibodies

Antibodies that exist in the joints before the onset of rheumatoid arthritis can cause pain even in the absence of arthritis, researchers from Karolinska Institutet in Sweden report. The researchers believe that the finding, ...

Arthritis & Rheumatism

'Locking' an arthritis drug may be key to improving it

Attaching a removable lock to an arthritis drug can make it safer and more effective, according to a new study publishing June 13 in the open-access journal PLOS Biology led by Wen-Wei Lin of Kaohsiung Medical University, ...

HIV & AIDS

The three big studies pushing at the frontiers of HIV prevention

There are an estimated 5000 new HIV transmissions every day. Around 70% of the 37 million people living with HIV globally are in sub-Saharan Africa. Of the 1.8 million new HIV transmissions worldwide in 2017, 800 000 occurred ...

Diseases, Conditions, Syndromes

Clues to building a better herpes vaccine

Efforts to develop an effective vaccine for genital herpes, a common sexually transmitted disease, have largely failed. In a new study published in Nature, Yale researchers explore why, and their findings could lead to a ...

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Antibody

Antibodies (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.

This text uses material from Wikipedia, licensed under CC BY-SA