Allergy-immunology glossary

Immune A complex formed by the non-covalent binding of an antibody and an complex antigen. Because each antibody molecule has a minimum of two antigen-binding sites and many antigens are multivalent, immune complexes can vary greatly in size 1. Immune complexes may form because of overproduction of antibodies to microbial antigens or as a result of autoantibody production 2. Immune complexes may activate the classical complement pathway or the Fc receptor-mediated phagocyte activation 2. Antigen-antibody complexes are mediators of type III immune responses. These include serum sickness and the arthus reaction. Evidence supports a pathogenic role for immune complexes in many other immunologic diseases