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Updated: Jul 4, 2026

Characterization of Proteins by Size-Exclusion Chromatography Coupled to Multi-Angle Light Scattering (SEC-MALS)
Published on: June 20, 2019
Characterisation of the 1st SSI purified MBL standard
Inga Laursen1, Peter Højrup, Gunnar Houen
1Statens Serum Institut, Copenhagen, Denmark. inl@ssi.dk
Background:
Mannan-binding lectin (MBL) is of importance in innate immunity. MBL-deficiency, the most common immune defect, is significant in several clinical contexts. The request for MBL diagnostic is increasing, hence we developed a high-purity MBL standard assigned with a traceable value.
Methods And Results:
The standard material was produced from human plasma; and the protein concentration determined by amino acid analysis after a preceding desalting. The standard value was assessed by two series of sub-sample analyses from nine vials by the grand mean: 235.7 microg protein/ml (range 191.1-280.3 microg/ml). The loss during desalting was 7% and the protein content 253.4 microg/ml after correction. After SDS/PAGE the MBL content was estimated by densitometric scanning. The MBL band (non-MBL bands being MASPs) comprised 76%. Therefore, the standard was assigned a value of 192.6 microg MBL/ml (range 156.0-229.2 microg/ml). A calibrated time-resolved immuno-flourescence assay was used for stability evaluation of the MBL standard, after transfer from -80 degrees C, showing stability for at least 10 days at 25 degrees C, 14 days at 5 degrees C, and 16 weeks at -20 degrees C.
Conclusion:
The 1st SSI purified MBL standard has been produced, and assigned the value 192.6 microg MBL/ml, traceable to an accurate realisation of the unit.

