B-cell receptor

B-cell receptor is a type of protein found on the surface of B cells, a type of white blood cell. These receptors are used by B cells to recognize specific antigens, which are substances that the body recognizes as foreign. When a B cell receptor binds to its specific antigen, it triggers the B cell to produce antibodies against that antigen.

Structure

The B-cell receptor consists of two parts: a B-cell co-receptor and an antigen-binding fragment. The B-cell co-receptor is a complex of proteins that includes CD19, CD21, and CD81. The antigen-binding fragment is made up of two identical heavy chains and two identical light chains, each with a variable region that can bind to a specific antigen.

Function

The primary function of the B-cell receptor is to recognize and bind to specific antigens. This binding triggers a series of events within the B cell, leading to the production of antibodies that can neutralize the antigen. In addition, the binding of the B-cell receptor to an antigen can also stimulate the B cell to divide and produce more B cells, a process known as clonal expansion.

Role in Immunity

B-cell receptors play a crucial role in the immune response. They allow B cells to recognize and respond to a wide variety of antigens, including bacteria, viruses, and other foreign substances. This recognition and response is a key part of the body's defense against infection.

Clinical Significance

Abnormalities in the B-cell receptor can lead to a variety of health problems, including autoimmune diseases, allergies, and certain types of cancer. For example, some forms of non-Hodgkin lymphoma are caused by mutations in the genes that code for the B-cell receptor.

See Also

• Antibody
• Immune system
• Antigen
• B cell

B-cell receptor

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