In immunology, a paratope, also known as an antigen-binding site, is the part of an antibody which recognizes and binds to an antigen.
[1][2] Each paratope is made up of six complementarity-determining regions - three from each of the light and heavy chains - that extend from a fold of anti-parallel beta sheets.
The paratopes on B-cell receptors binding to their specific epitope is a critical step in the adaptive immune response.
[3] Thus, many different species have developed ways to bypass this restriction and increase the diversity of possible paratopes.
In cows, an extra-long complementarity-determining region is considered to have an essential role in diversifying paratopes.