Complementarity Determining Region (CDR) refers to a specific section within the variable domains of immunoglobulin molecules, also known as antibodies. These regions are responsible for recognizing and binding to specific antigens, which are foreign substances such as bacteria, viruses, or toxins.
CDRs are actually three highly variable loop-like sequences located within the structure of both the light and heavy chains of an antibody. They are designated as CDR1, CDR2, and CDR3, with each having a unique sequence and structure. The combination of these three loops forms the antigen-binding site on the antibody.
The importance of CDRs lies in their ability to confer specificity to the immune response. Each antibody produced by the immune system has a different set of CDRs, allowing for the recognition and binding of a vast array of antigens. This diversity is achieved through a process known as V(D)J recombination, where genetic elements encoding for the different CDRs are rearranged during the development of B cells.
The CDRs play a crucial role in immune recognition and defense mechanisms by enabling the antibody to selectively bind to a specific antigen. The binding occurs when the CDRs interact with the surface of the antigen, leading to the activation of immune responses to eliminate the invading pathogen or toxin.
In summary, Complementarity Determining Regions are essential components of antibodies that enable them to recognize and bind to specific antigens, thereby initiating immune responses and protecting the body against potential threats.
