AN ENDOGENOUS LECTIN, GALECTIN-3 (EPSILON-BP MAC-2), POTENTIATES IL-1PRODUCTION BY HUMAN MONOCYTES/

Galectin-3 is a member of a growing family of beta-galactoside-binding animal lectins and previously designated as epsilon BP (IgE-binding p rotein) by this laboratory and as Mac-2, CBP35, L-34 and L-29 by other researchers. While possible intracellular functions have been propose d for galectin-3, existing data also suggest an extracellular modulato ry role of this lectin, For example, epsilon BP/Mac-2 was found to be secreted by various cells and capable of activating mast cells, possib ly through cross-linking of cell surface glycoproteins involved in cel l activation. In this study, we showed that epsilon BP bound to human monocytes via its lectin function. Furthermore, we found that epsilon BP potentiated IL-1 production by monocytes in a manner that was inhib itable by the saccharide ligand of epsilon BP. The results further sup port a role of this lectin in potentiating activities of inflammatory cells and thereby amplifying inflammatory responses.