The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Opsonization is a term that refers to an immune process where particles such as bacteria are targeted for destruction by an immune cell known as a phagocyte. The process of opsonization is a means of identifying the invading particle to the phagocyte. Without the opsonization process the recognition and destruction of invading agents such as bacteria would be inefficient.
The process of opsonization begins when the immune system recognizes a particle (e.g., a bacterium) as an invader. The recognition stimulates the production of antibodies that are specific for the antigenic target. Certain antibody molecules are stimulated to bind to the surface of the particle. Typically, the binding molecules are a type of antibody classified as IgG. As well, proteins involved in the complement-mediated clearance of foreign material, specifically a protein designated C3b, can bind to the surface of the foreign object. Proteins such as IgG and C3b, which can promote opsonization, are designated as opsonins.
When the IgG antibodies bind to the invading bacterium, the binding is in a specific orientation. An antibody is somewhat "Y" shaped. The binding of IgG to the bacterium is via the branching arms of the "Y." The stalk of the molecule, which is termed the Fc region, then protrudes from the surface. The Fc region is recognized by a receptor on the surface of an immune cell called a phagocyte. When the Fc region is bound to the phagocytic receptor the invading particle is taken into the phagocyte and enzymatically digested.
The Cb3 complement protein can bind in a nonspecific manner to an invading particle. Phagocytes also contain surface receptors that recognize and bind Cb3. As with IgG, the binding of Cb3 to the phagocytes triggers a process whereby the invading particle is engulfed, surrounded, and taken inside the phagocytic cell for destruction.
Examples of phagocytic cells that can participate in opsonization are neutrophils and monocytes.
Bacteria that are associated with the development of infections typically possess a capsule, which is a layer of carbohydrate material. The capsular material encases the bacterial cell. The carbohydrate is not recognized as readily by the immune machinery of the body as is protein. As well, the penetration of antibodies through the capsule network to the surface of the bacterium is impeded. Thus, possession of a capsule can dampen the opsonization response.