degranulaatiossa

Degranulatio is a biological process primarily associated with immune cells, particularly mast cells, basophils, and certain types of dendritic cells. During degranulation, these cells release the contents of their intracellular granules—prepackaged vesicles filled with bioactive molecules—into the extracellular space. This process is a key component of the immune response, especially in allergic reactions and inflammation.

Mast cells and basophils store granules containing histamine, proteases (such as tryptase and chymase), cytokines, and other mediators. When activated by allergens, antibodies (e.g., IgE), or other stimuli, these cells undergo degranulation, rapidly releasing their contents. Histamine, for instance, promotes vasodilation and increased vascular permeability, contributing to symptoms like swelling and itching. Proteases can further amplify inflammation by activating other immune cells or degrading extracellular matrix components.

Degranulation is also observed in neutrophils and eosinophils, though their granules contain different enzymes and antimicrobial peptides. In neutrophils, degranulation occurs during phagocytosis or in response to microbial invasion, aiding in pathogen destruction. Eosinophils release granules rich in toxic proteins, particularly in parasitic infections or allergic responses.

The process is tightly regulated to prevent excessive tissue damage. Upon activation, cells undergo structural changes, including fusion of granule membranes with the plasma membrane, allowing contents to be expelled. Some cells, like mast cells, can also undergo piecemeal degranulation, where granules release their contents gradually rather than all at once.

Disruptions in degranulation regulation can lead to pathological conditions, such as anaphylaxis in severe allergic reactions or chronic inflammatory diseases. Research into degranulation mechanisms continues to inform the development of therapeutic interventions, including inhibitors of key mediators or signaling pathways involved in the process.