Specific granules are secretory vesicles found exclusively in cells of the immune system called granulocytes.
It is sometimes described as applying specifically to neutrophils,[1] and sometimes the term is applied to other types of cells.[2]
These granules store a mixture of cytotoxic molecules, including many enzymes and antimicrobial peptides, that are released by a process called degranulation following activation of the granulocyte by an immune stimulus.
Specific granules are also known as "secondary granules".[3]
Contents
Examples of cytotoxic molecule stored by specific granules in different granulocytes include:
- Neutrophil: alkaline phosphatase, lactoferrin, lysozyme, NADPH oxidase
- Eosinophil: cathepsin, major basic protein
- Basophil: heparin, histamine (not directly cytotoxic)
Clinical significance
A specific granule deficiency can be associated with CEBPE.[4]
References
- ^ "Definition: specific granule from Online Medical Dictionary".
- ^ Okuda M, Takenaka T, Kawabori S, Ogami Y (July 1981). "Ultrastructural study of the specific granule of the human eosinophil". J. Submicrosc. Cytol. 13 (3): 465–71. PMID 7334549.
- ^ John P. Greer; Maxwell Myer Wintrobe (1 December 2008). Wintrobe's clinical hematology. Lippincott Williams & Wilkins. pp. 173–. ISBN 978-0-7817-6507-7. Retrieved 10 November 2010.
- ^ Online Mendelian Inheritance in Man (OMIM): SPECIFIC GRANULE DEFICIENCY; SGD - 245480
External links