HK J Paediatr (new series) 2002;7:134-142 The Role of Mannose-Binding Lectin in Health and Disease

Abstract Mannose-binding lectin (MBL) is an important constituent of the innate immune defence system. The protein binds to the sugars decorating many microbial surfaces and subsequently activates the complement system through a specific protease called MASP-2. A comparison of the importance of the capsule and lipopolysaccharide (LPS) structures of selected Gram-negative organisms for the binding of MBL suggests that the LPS structure is of primary importance. For several clinically relevant organisms MBL binding leads to activation of C4 suggesting that this is a major pathway for oposonophagocytosis. MBL deficiency mainly results from three mutations in exon 1 of the gene and is associated with both increased susceptibility to infections and autoimmune disease. Recent evidence indicates that the protein also modulates disease severity, possibly through a dose dependent influence on cytokine production. Key words Complement activation; Innate immune defence; Mannose-binding lecti