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Identification of human complement Factor H as a ligand for L-selectin
1Cellular Biochemistry Unit, Glaxo-Wellcome Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK. RM18326@glaxowellcome.co.uk
The Biochemical Journal
|June 23, 1999
Summary
Researchers identified human Factor H as a novel L-selectin ligand involved in leukocyte activation and inflammation. This discovery sheds light on immune cell recruitment and function.
Area of Science:
- Immunology
- Molecular Biology
- Biochemistry
Background:
- Selectins (E-, P-, L-selectins) mediate leukocyte recruitment during inflammation.
- L-selectin is crucial for leukocyte tethering, rolling, and activation.
- Human L-selectin ligands in serum remain largely uncharacterized.
Purpose of the Study:
- To identify and characterize human serum ligands for L-selectin.
- To investigate the functional role of identified ligands in leukocyte activation.
Main Methods:
- L-selectin affinity chromatography and ion-exchange chromatography were used for ligand isolation.
- Mass spectrometry (MS) and protein database searching identified the 170 kDa glycoprotein.
- Functional binding assays and tumor necrosis factor-alpha (TNF-alpha) secretion assays were performed.
Main Results:
- Three major glycoproteins (170 kDa, 70 kDa, 50 kDa) were isolated.
- The 170 kDa protein was identified as human complement Factor H.
- Factor H specifically binds L-selectin, inducing TNF-alpha secretion, which is dependent on Factor H glycosylation.
Conclusions:
- A post-translationally modified form of human plasma Factor H is a potential physiological ligand for L-selectin.
- Factor H interaction with L-selectin modulates leukocyte activation and inflammatory responses.
- This finding offers new insights into L-selectin-mediated immune cell trafficking.