An acute-phase protein (see acute-phase response) secreted into blood plasma by the liver in response to infection. It forms part of the innate immune response by binding to bacterial cells, enhancing their susceptibility to ingestion by phagocytic cells, particularly monocytes, and triggering the complement cascade leading to target cell destruction. The MBL molecule has up to six clusters of carbohydrate-recognition domains, which bind to appropriately spaced mannose or fucose residues on bacterial surfaces. The spacing of the residues is crucial in discriminating bacterial cells from self tissues. See also lectin.
Subjects: Biological Sciences.