Mannan-binding lectin (MBL)

a circulating plasma, acute phase protein of hepatic origins that plays an important role in the innate immune response to infection, because it binds to carbohydrates on bacteria, and subsequently activates the complement pathway. It is a key feature in the lectin pathway of complement activation. Deficiency of MBL can lead to recurrent infections, particularly in childhood. MBL is polymorphic in the population and a deficiency of MBL is likely due to a defective protein, which cannot form oligomers and is also associated with some autoimmune diseases such as rheumatoid arthritis.