The Jekyll and Hyde nature of antibodies

Antibodies are proteins that protect us against any foreign bodies, or antigens, that we encounter. Antigens include proteins on viruses or toxins made by either bacterial cells or large intestinal parasites. Antibodies bind to antigens and in doing so direct the body’s defence against the invading organism. Antibodies are easily detected in, and isolated from, the blood. This means that antibodies can be used to diagnose illness and to prevent or reduce disease. However, it’s not all good news — antibodies can also cause disease. This article reveals some of the bad effects of antibodies.

Adrienne Edkins and William Cushley

Coloured scanning electron micrograph of pollen grains from assorted flowers. Pollen stimulates IgE antibody production in sensitive people, producing an allergic reaction. ×650

AMI Images/SPL

Antibody Antigen Immunoglobulin Monoclonal antibody Disease therapy

Our immune system destroys anything that it does not recognise as a ‘self’ tissue or molecule. This presents a particular problem in pregnancy, as illustrated by rhesus disease. A protein called the rhesus D antigen is found on the surface of red blood cells. Some people make this protein and are called RhD+, others do not and are therefore RhD−. In RhD– women, the RhD protein is just as foreign to their immune system as measles virus protein, and is equally good at provoking an immune response.