Galectin-9 Changes Its Function to Maintain Homeostasis

Abstract

Galectin-9 (Gal-9)/Ecalectin was first identified as a T cell-derived eosinophil chemoattractant. We found that Gal-9 plays a role in not only the accumulation but also the activation of eosinophils in experimental allergic models and human allergic patients; Gal-9 was shown to induce eosinophil chemotaxis in vitro and in vivo and activated eosinophils in various aspects. Recent studies, however, showed that Gal-9 has other functions in the differentiation, maturation, aggregation, adhesion, and death of various cells. Presently, we and other groups are in the process of investigating the function of Gal-9 in a variety of physiological and pathological conditions. In this article, we will show the in vivo therapeutic effects of Gal-9 in various disease models (both hyper-immune and immune-compromised conditions), suggesting that Gal-9’s immune function changes according to the context. Indeed, the accumulated evidence suggests that Gal-9 orchestrates a variety of biological phenomena to maintain homeostasis.