If you’re wondering “What is an antibody?” then read on! Antibodies are proteins made by the immune system in response to an antigen. Antigens are substances that invade our bodies and stimulate our immune system to respond by producing antibodies. Each antibody binds to a particular antigen, which helps our body destroy that antigen. Some antibodies directly destroy antigens while others merely make it easier for white blood cells to destroy them.
An antibody is a molecule secreted into our blood or mucosa. When it binds to an antigen, it activates the complement system, which destroys the bacterial cell by punching holes in its cell wall. Antibodies also facilitate phagocytosis, the process in which our body recognizes and fights foreign substances. Antibodies are also part of our immune system, enabling our body to fight off harmful bacteria and viruses.
Antibodies bind to an antigen through a specific recognition surface called an epitope. Antibodies recognize these areas as antigens, and the antigens attach to these receptors. Hence, it is important for antigen presentation to trigger the activation of T cells. However, antigens that have only one epitope may not be recognizable to antibodies, and vice versa. Moreover, different antigens have different types of epitopes.
In addition to the Fab fragment, an antigen can bind to an antibody through the Fc portion of the antibodies. This is the hinge region of the antibody. In this region, pepsin acts. Pepsin cleaves the antibody into two fragments, the first one called the Fab fragment. The Fc fragment is the carboxy-terminal part of the heavy chains and is responsible for initiating the biological activity after binding the antigen.
The light chains in an immunoglobulin contain two classes of molecules called kappa chain and lambda chain. Lambda chains are larger than kappa chains, and kappa chains are smaller than the lambda chain. The kappa and lambda chains of an antibody are covalently linked in order to form a protein. They help the immune system fight infections by triggering the body’s response.
Antibodies attach to a particular antigen and attract cells that can kill a pathogen. These immune system cells are called lymphocytes and are made in the bone marrow and thymus. Antibodies bind to specific antigens and inhibit the pathogen’s ability to invade our body. Antibodies also block receptors in the host cell, making it difficult for pathogens to infect us.