opsonin
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- opsonin
-
any substance that binds to particulate antigens and induces their phagocytosis by macrophages and neutrophils. In current usage the term is used to refer to substances of two types, opsonizing antibodies (IgM, IgG1, and IgG3 immunoglobulins specific for the antigen) and certain complement fragments (C3b, C3d, and C4b, which become bound to the antigen during complement activation), both of which trigger phagocytosis by binding to specific cell-surface receptors, Fc receptors, and C3b receptors on neutrophils and macrophages and C3d receptors on macrophages.
Used in 1 Term definition
Used in 1 Term definition