An endogenous lectin, galectin-3 (ε{lunate}BP / Mac-2), potentiates IL-1 production by human monocytes

Galectin-3 is a member of a growing family of β-galactoside-binding animal lectins and previously designated as ε{lunate}BP (IgE-binding protein) by this laboratory and as Mac-2, CBP35, L-34 and L-29 by other researchers. While possible intracellular functions have been proposed for galectin-3, existing data also suggest an extracellular modulatory role of this lectin. For example, ε{lunate}BP/Mac-2 was found to be secreted by various cells and capable of activating mast cells, possibly through cross-linking of cell surface glycoproteins involved in cell activation. In this study, we showed that ε{lunate}BP bound to human monocytes via its lectin function. Furthermore, we found that ε{lunate}BP potentiated IL-1 production by monocytes in a manner that was inhibitable by the saccharide ligand of ε{lunate}BP. The results further support a role of this lectin in potentiating activities of inflammatory cells and thereby amplifying inflammatory responses.