MAINTENANCE OF GRANULOCYTE NUMBERS DURING ACUTE PERITONITIS IS DEFECTIVE IN GALECTIN-3-NULL MUTANT MICE

Galectin-3, also known as the macrophage marker Mac-2, is a member of a family of structurally related animal lectins that exhibit specifici ty for beta-galactosides. In order to investigate the role of galectin -3 in acute inflammation, we have compared the number of leucocytes pr esent in the peritoneal cavity of wild type and galectin-3 null mutant mice after intraperitoneal (i.p.) injection of thioglycolate broth. A t day 1 after injection, we found no difference in the recruitment of mononuclear phagocytes and granulocytes to the peritoneal cavity. Howe ver, 4 days after thioglycolate injection, galectin-3 mutant mice exhi bited a significantly reduced number of recoverable granulocytes compa red to wild-type animals. As mutant granulocytes did not exhibit an ac celerated rate of apoptosis and their uptake by macrophages appeared t o be unaffected by the mutation, the phenotype described here suggests that galectin-3 participates in an additional level of control during the resolution of acute inflammation.