epitopa

Epitopa is a term used in immunology to describe specific sites on an antigen that are recognized by the immune system, particularly by antibodies or T-cell receptors. These sites are essentially the molecular structures that the immune system "sees" and binds to. An antigen, which can be a protein, carbohydrate, or other molecule, can possess multiple epitopa. The immune response to an antigen is directed at these individual epitopa.

There are two main types of epitopa: conformational and linear. Conformational epitopa are formed by amino acid residues that are brought together by the three-dimensional folding of a protein. These epitopa are dependent on the protein's overall structure. Linear epitopa, on the other hand, are composed of a continuous sequence of amino acids along the polypeptide chain. They do not rely on the protein's folding. Antibodies can bind to both types of epitopa, while T-cell receptors typically recognize linear epitopa presented on MHC molecules. Understanding epitopa is crucial for developing vaccines, diagnostic tests, and immunotherapies, as it allows for targeted immune responses.