- Antibody opsonization
Antibody opsonization is the process by which a pathogen is marked for ingestion and destruction by a
phagocyte. Opsonization involves the binding of an opsonin, i.e., antibody, to a receptor on the pathogen's cell membrane [ [http://cancerweb.ncl.ac.uk/cgi-bin/omd?query=opsonisation Definition: opsonization from Online Medical Dictionary ] ] . After opsonin binds to the membrane, phagocytesare attracted to the pathogen. The Fab portion of the antibody binds to the antigen, whereas the Fc portion of the antibody binds to an Fc receptoron the phagocyte, facilitating phagocytosis. [Parham, P. (2005). "The Immune System," Garland Science Publishing, New York, NY.] The receptor-opsin complex can also create byproducts like C3band C4bwhich are important components of the complement system. These components are deposited on the cell surface of the pathogen and aid in its destruction [Kumar, V., Abbas, A. K., & Fausto, N. (2005). Pathologic basis of disease. Philadelphia: Elsevier Saunders] .
The cell can also be destroyed by a process called antibody-dependent cellular
cytotoxicityin which the pathogen does not need to be phagocytosed to be destroyed. During this process, the pathogen is opsonized and bound with the antibody IgG. The antibody triggers a release of lysis products from cells like monocytes, neutrophils, eosinophils, and natural killer cells. This process can cause inflammation of surrounding tissues and damage to healthy cells. (Antibody Opsonization)
Wikimedia Foundation. 2010.