Specific granules

Specific granules are a secretory vesicles found exclusively in cells of the immune system called granulocytes. They are also known as secondary granules. 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.

Examples of cytotoxic molecule stored by specific granules in different granulocytes include:


 * Neutrophil: alkaline phosphatase, lactoferrin, lysozyme, myeloperoxidase, NADPH oxidase


 * Eosinophil: cathepsin, major basic protein


 * Basophil: heparin, histamine