antigenreceptorer

Antigen receptors are complex molecular structures found on the surface of immune cells, such as B cells and T cells, in the body's immune system. They play a crucial role in the recognition and binding of antigens, which are substances foreign to the body, such as bacteria, viruses, and other pathogens.

The structure of antigen receptors is unique to each immune cell and is responsible for facilitating the unique recognition of antigens. On B cells, the antigen receptor is a molecule known as an antibody, which is produced through a process called affinity maturation. Antibodies have a binding site that can recognize and bind to a specific antigen, triggering a series of immune responses to eliminate or neutralize the threat.

On T cells, the antigen receptor is called a T cell receptor (TCR). TCRs are composed of two chains, the alpha and beta chains, that combine to form a unique recognition site. The TCR binds to an antigen-presenting cell (APC) that presents a fragment of the antigen on its surface, allowing the T cell to recognize and respond to infected cells or tumor cells.

In both cases, the binding of the antigen receptor to an antigen leads to signal transduction, which activates the immune cell and triggers an immune response. Antigen receptors are highly specific and sensitive, with the ability to recognize and differentiate between millions of unique antigens.

The function of antigen receptors is essential for the body's immune response and serves as a first line of defense against pathogens and other foreign substances. Dysregulation of antigen receptor function has been implicated in various autoimmune diseases and immunodeficiency disorders.