Discrete MBL-MASP complexes show wide inter-individual variability in concentration: data from UK vs Armenian
K R Mayilyan1, J S Presanis, J N Arnold
1MRC Immunochemistry Unit, Department of Biochemistry, Oxford University, Oxford, UK.
International Journal of Immunopathology and Pharmacology
|October 10, 2006
Summary
Mannan-binding lectin (MBL) and its associated serine proteases (MASP) play roles in the immune system. This study found differences in MBL-MASP complex activity between UK and Armenian populations, suggesting MASP-2 levels influence complement activation.
Area of Science:
- Immunology
- Complement System
- Protease Activity
Background:
- Mannan-binding lectin (MBL) circulates with MBL-associated serine proteases (MASPs) and activates the complement system upon microbial binding.
- MASP-2 activation is crucial for the complement cascade, while MASP-1 and MASP-3 roles are less defined.
- MBL levels and MASP activities can be influenced by factors like aging and smoking.
Purpose of the Study:
- To evaluate MBL levels and MBL-bound MASP-1 and MASP-2 activities in healthy UK and Armenian populations.
- To investigate the relationship between MBL, MASP activities, and demographic factors like age and smoking.
- To compare the normalized MASP activities between the two distinct populations.
Main Methods:
- Quantification of MBL levels in plasma.
- Assay of MBL-bound MASP-1 and MASP-2 activities.
- Statistical analysis to compare MBL and MASP parameters between UK and Armenian populations.
- Normalization of MASP activities to MBL levels to assess complex concentration.
Main Results:
- MBL-bound MASP-2 activity showed a decline with aging.
- MBL levels correlated positively with smoking.
- Significant differences were observed in MBL and MBL-bound MASP-1 activity between populations, but not in MBL-bound MASP-2 activity.
- Normalized MASP-2 activity was over twofold higher in UK individuals compared to Armenians.
- High MBL concentrations may be associated with excess free MBL not bound to MASPs.
Conclusions:
- Complement activation efficiency, mediated by the MBL-MASP-2 complex, is influenced by both MBL quantity and MASP-2 concentration.
- Differences in normalized MASP-2 activity between populations suggest variations in MASP-2 serum levels.
- The findings highlight the complex interplay between MBL, MASPs, and complement function, with potential implications for immune response variability.
