Galectin-9 (Gal-9) is a member of animal lectins that have an affinity to beta-galactosides. Gal-9 was first cloned from tumor tissues of Hodgkin’s disease that is frequently characterized by eosinophilia. Galectins exhibit various biological functions, such as cell aggregation and adhesion, proliferation,cell death, modulation of inflammation and metastasis.First, Gal-9/ecalectin was identified as a potent T cellderived eosinophil chemoattractant (ECA).
Gal-9 exhibits ECA activity in vitro and in vivo, activates eosinophils, and influences eosinophil survival. It requires divalent galactoside- binding activity but not its linker peptide to exhibit its functions , and some matrix metalloproteinases are involved in the release.