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Updated: May 6, 2026
Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells
Published on: January 29, 2014
Assay for estimation of the functional activity of the mannan-binding lectin pathway of the complement system
Troels R Kjaer1, Steffen Thiel
1Department of Biomedicine, Aarhus University, Aarhus, Denmark.
Abstract:
Mannan-binding lectin (MBL) is a soluble pattern recognition molecule of the innate immune system. It is found in plasma in complex with MBL-associated serine proteases (MASPs). When MBL recognizes foreign, e.g., the surface of some microorganisms, or altered host surfaces the MASPs are activated and this will in turn lead to the initiation of the complement system, i.e., activation of complement by the MBL pathway. This will end up in increased phagocytosis of the microorganism and killing by insertion of pore structures in the membrane of the microorganisms. Lack of MBL seems significant in specific situations, e.g., in immunocompromised individuals were MBL is important in battling infections and, e.g., in ischemia/reperfusion injuries were MBL can have a negative inflammatory generating, and thus tissue destructive role, as it recognizes epitopes emerging in the ischemic tissue. It may thus be relevant in several situations to test for the presence of the MBL pathway in human sera. Here we describe a functional assay for estimation of MBL pathway activity by detection of complement factor deposition onto microtiter plate wells coated with a physiological relevant ligand for MBL.
Insights
Mannan-binding lectin (MBL) is crucial for innate immunity, aiding in pathogen clearance and potentially exacerbating tissue damage in certain conditions. A new functional assay measures MBL pathway activity in human serum.
Area of Science:
- Immunology
- Innate Immunity
- Complement System
Background:
- Mannan-binding lectin (MBL) is a key pattern recognition molecule in the innate immune system.
- MBL functions in complex with MBL-associated serine proteases (MASPs), initiating the complement cascade upon recognizing foreign or altered self-surfaces.
- MBL plays a role in combating infections and can contribute to inflammation in conditions like ischemia/reperfusion injury.
Purpose of the Study:
- To develop and describe a functional assay for estimating MBL pathway activity.
- To enable the assessment of MBL pathway presence in human sera for various clinical contexts.
Main Methods:
- The assay utilizes microtiter plate wells coated with a physiological ligand for MBL.
- Complement factor deposition onto the coated wells is detected to quantify MBL pathway activity.
Main Results:
- A functional assay for MBL pathway activity was successfully developed.
- The assay allows for the estimation of MBL pathway function through complement factor deposition.
Conclusions:
- The developed assay provides a means to assess MBL pathway activity in human serum.
- This assay is relevant for situations where understanding MBL's role in infection or inflammation is important.
