ONTOGENY OF HUMAN MANNAN-BINDING PROTEIN, A LECTIN OF THE INNATE IMMUNE-SYSTEM

Mannan-binding protein (MBP) is a member of the collectins. These lect ins are composed of polypeptide chains which contains a collagen-like region and a calcium dependent carbohydrate recognition domain (named a C-type CRD). MBP binds via the CRD to carbohydrate structures on mic roorganisms. MBP can activate the complement system when bound to carb ohydrate. MBP is thus thought to play a role in the defence against mi croorganisms. The present report describes the ontogeny of MBP. The le vel of MBP increase during the first 3 months of life, at which time a stable level is reached, comparable to that seen in adults. On averag e, the level of MBP at term was 37% of the post 3-month level. Measure ments on infants born prematurely showed a 3-fold increase in MBP conc entration from the time of birth at around 30 weeks from conception to the 10th week of life.