Antibodies, scientifically referred to as immunoglobulins, are vital large proteins that play a significant role in identifying and eradicating foreign invaders and unrecognized proteins within the body. These remarkable proteins, along with B and T cells, form an integral part of the adaptive immune system. Unlike the innate immune system, which provides immediate defense against any threat, the adaptive immune system is “learned” and highly tailored to specific dangers.
Antibodies are of utmost importance in the development of vaccines, as they are responsible for providing immunity against various common diseases. However, it is essential to acknowledge that antibodies can also be the culprits behind numerous autoimmune diseases.
Understanding the Structure of Antibodies
Antibodies possess a distinctive Y-shaped structure and are composed of four polypeptides or chains of amino acids. These chains comprise two heavy chains and two light chains, each containing numerous domains. The structure of an antibody can be divided into three primary regions, each serving a specific function. The upper part of the Y-shaped antibody is made up of two antigen-binding fragments (Fab), while the trunk is formed by a crystallizable fragment (Fc).
Fab Fragment: The Key to Antibody-Antigen Interactions
The Fab fragment plays a crucial role in the interaction between antibodies and antigens, which are foreign substances like bacteria or viruses. Comprising a heavy and light chain, the Fab fragment consists of both control and variable domains. It is within the variable domain that hypervariable domains are found, forming the antigen-binding site, also known as the paratope.