Antibody

The antibody (AN-ti-BOD-ee) is a fundamental component of the immune system, specifically produced by white blood cells, or lymphocytes, in response to the introduction of a foreign substance, known as an antigen. Each antibody is specifically designed to bind to a particular antigen, a function critical to the immune response.

Antibody

Normal plasma blood cells

Antibody_IgG2

Production and Function

Antibodies, also known as immunoglobulins, are produced by a type of white blood cell called a B lymphocyte, or B cell. When an antigen enters the body, it stimulates the B cell to produce antibodies that specifically match the antigen.

The production of antibodies is a key aspect of the immune response, which occurs when the body is exposed to viruses, bacteria, or other foreign substances. The specific binding of an antibody to an antigen helps to neutralize the antigen or mark it for destruction, hence providing immunity against the substance.

Mechanisms of Action

Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies bind to antigens, neutralizing them directly. This prevents the antigen from entering or damaging the cells. Others coat the antigen, making it easier for white cells (phagocytes) to identify and engulf them.

Classes of Antibodies

There are five major classes of antibodies: IgG, IgM, IgA, IgD, and IgE. Each class has different functions in the immune response.

Clinical Significance

Antibodies have a significant role in diagnostics and therapeutics in medicine. They are used in diagnostic tests for various diseases, including viral and bacterial infections, autoimmune diseases, and allergies. In therapeutics, monoclonal antibodies are used to treat a wide range of conditions, including cancers, autoimmune diseases, and infectious diseases.

See Also

• Immune system
• Antigen
• Lymphocyte
• B cell
• Monoclonal antibodies

Antibody Resources
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