Mannose Binding Lectin (MBL)
The determination of MBL concentrations in serum may be useful for the elucidation of suspected immune defects and as a prognostic indicator alerting to the need for heightened therapeutic or prophylactic measures in immunosuppressed patients, including patients receiving cancer chemotherapy and patients with cystic fibrosis, SLE, or rheumatoid arthritis.
Mannose-binding lectin (MBL) is a multimeric, carbohydrate-binding protein produced in the liver and secreted into the blood that plays an important role in the innate immune response against invading microörganisms.1-6 MBL is a member of a family of the “collections” proteins, so named because they have a collagen-like region and a lectin region. Functional MBL is an oligomer complex of three identical monomer chains connected together through a triple helix of the collagen-like regions. The three C-terminal lectin carbohydrate recognition domains of the individual component proteins stick out from the triple helix in a manner that, by electron microscopy, resembles three flowers protruding from a single stalk. Many pathogens, including viruses, bacteria, fungi, protozoa, have surface sugars that are absent from mammalian cell surfaces. The lectin domains of the MBL complex recognize the spatial arrangement of carbohydrate sugar residues on pathogen surfaces and bind to them. Specific enzymes (MBL-associated serine proteases or MASPs) are activated when MBL binds to microbial carbohydrate surfaces and in turn activate complement via the MBL or lectin pathway. MBL binding to pathogens surfaces activates the complement system, causing inflammation, increased vascular permeability, and the recruitment and activation of phagocytes. MBL binding also facilities recognition and ingestion of the foreign entity by phagocytes in a process referred to as opsonization.
Gel-barrier tube or red-top tube
0.1 mL (Note: This volume does not allow for repeat testing.)
No special patient preparations are necessary.
If a red-top tube is used, transfer separated serum to a plastic transport tube.
Maintain specimen at room temperature. Stable 14 days. Stable refrigerated or frozen for 14 days. Freeze/thaw cycles: stable x3.
Nonserum sample; hemolyzed or hyperlipemic sample received.