antigen binding

Definition

Target type: molecularfunction

Binding to an antigen, any substance which is capable of inducing a specific immune response and of reacting with the products of that response, the specific antibody or specifically sensitized T-lymphocytes, or both. Binding may counteract the biological activity of the antigen. Antigen binding by an MHC protein complex allows the antigen to be displayed to a T cell or NK cell. [GOC:jl, ISBN:0198506732, ISBN:0721662544]

Antigen binding is a fundamental process in the immune system that involves the specific recognition and interaction between an antigen and an antibody or T cell receptor (TCR). It is a highly specific process, with antibodies and TCRs capable of discriminating between a vast array of different antigens. The molecular function of antigen binding can be broken down into several key steps:

1. **Recognition**: Antibodies and TCRs possess a variable region that is specifically designed to bind to a particular antigen. This region contains unique amino acid sequences that form a three-dimensional structure that complements the shape of the antigen, allowing for a tight and specific interaction.
2. **Binding**: Once the antibody or TCR recognizes its corresponding antigen, it forms a non-covalent bond with the antigen. This binding is typically mediated by weak interactions, such as hydrogen bonds, van der Waals forces, and electrostatic interactions.
3. **Signal transduction**: The binding of an antigen to an antibody or TCR triggers a series of intracellular signaling events. These events can lead to a variety of downstream effects, including the activation of immune cells, the production of cytokines, and the elimination of pathogens.

The molecular basis of antigen binding is complex and involves the interplay of various molecular forces. The specificity and affinity of antigen binding are crucial for the proper functioning of the immune system. It allows the immune system to distinguish between self and non-self antigens, mount targeted immune responses against pathogens, and prevent autoimmune reactions.
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Proteins (1)

Compounds (1)