Eotaxin

Eotaxin is the common name for a small secreted chemokine known scientifically as CCL11, with the original designation eosinophil chemotactic factor of anaphylaxis. It is a member of the C-C chemokine family and functions primarily as a chemotactic signal for eosinophils, guiding these cells to sites of inflammation.

Mechanistically, eotaxin binds to the CCR3 receptor on eosinophils, basophils, and some T helper cells, promoting migration toward higher concentrations of the chemokine. It is produced by a variety of cell types, including airway epithelial cells, endothelial cells, fibroblasts, and macrophages. Its expression is upregulated by inflammatory signals such as IL-4, IL-13, TNF-α, and IL-1β, linking it to allergic and inflammatory conditions.

The eotaxin family includes several related chemokines, notably eotaxin-1 (CCL11), eotaxin-2 (CCL24), and eotaxin-3 (CCL26). These ligands share a capacity to attract eosinophils through CCR3 and can have overlapping as well as distinct tissue distribution and potency in various inflammatory contexts.

Clinical relevance is most evident in diseases characterized by eosinophilic inflammation, such as asthma and atopic dermatitis, where elevated eotaxin levels have been reported. Because of its role in eosinophil recruitment, the eotaxin/CCR3 axis has been explored as a therapeutic target, with approaches including CCR3 antagonists and anti-eotaxin strategies; however, these have not become standard treatments. Eotaxin levels are used in research as biomarkers of eosinophilic activity in certain inflammatory conditions.