epitoppeista

Epitopes are specific regions on an antigen that are recognized by the immune system, particularly by antibodies and T cell receptors. An antigen is a molecule that can trigger an immune response. Epitopes are also referred to as antigenic determinants. The immune system, through its lymphocytes, has receptors that are highly specific for particular epitopes. When an antibody binds to an epitope, it is a lock-and-key interaction, where the antibody's binding site is the lock and the epitope is the key.

There are two main types of epitopes: linear and conformational. Linear epitopes are formed by a continuous sequence of amino acids in a protein. Conformational epitopes, on the other hand, are formed by amino acids that are brought together by the folding of the protein, even if they are not adjacent in the primary sequence. These conformational epitopes can be disrupted if the protein denatures or unfolds.

The size and shape of an epitope are crucial for its recognition. Antibodies typically recognize epitopes that are relatively small, often consisting of 5-15 amino acids. T cell receptors recognize epitopes that are presented on the surface of cells in conjunction with major histocompatibility complex (MHC) molecules. Understanding epitopes is fundamental in immunology, vaccine development, and the design of diagnostic tests.