Eosinophils are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along with mast cells and basophils, they also control mechanisms associated with allergy and asthma. They are granulocytes that develop during hematopoiesis in the bone marrow before migrating into blood, after which they are terminally differentiated and do not multiply. They form about 2 to 3% of WBC's.
These cells have large acidophilic cytoplasmic granules, which show their affinity for acids by their affinity to eosin, a red dye. The staining is concentrated in small granules within the cellular cytoplasm, which contain many chemical mediators, such as eosinophil peroxidase, ribonuclease (RNase), deoxyribonucleases (DNase), lipase, plasminogen, and major basic protein. These mediators are released by a process called degranulation following activation of the eosinophil.
The role of eosinophils in asthma. An overview of the main stimuli for eosinophilic airway inflammation (gray boxes) and the means by which eosinophils elicit the main pathophysiological changes associated with asthma (green boxes). Abbreviations: MBP, major basic protein; EPO, eosinophil peroxidase; IL, interleukin; TGF-β, transforming growth factor-β; GM-CSF, granulocyte–macrophage colony-stimulating factor; PGD2, prostaglandin-D2; 5-oxo-ETE, 5-oxo 6, 8, 11, 14-eicosatetraenoic acid; PAMPs, pathogen associated molecular patterns; DAMPs, damage associated molecular patterns; Ig, immunoglobulin.
The Biology of Eosinophils and Their Role in Asthma, 2017
The Human Eosinophil
Functions of tissue-resident eosinophils, 2017
Antagonism between C/EBPβ and FOG in eosinophil lineage commitment of multipotent hematopoietic progenitors 2000
kynurenine and eosinophils