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Migration of polymorphonuclear leukocytes through human amnion membrane--a scanning electron microscopic study
1Department of Biochemistry, University of Bielefeld, Faculty of Chemistry, F.R.G.
Biological Chemistry Hoppe-Seyler
|July 1, 1992
Summary
Polymorphonuclear leukocytes degrade basement membranes via metalloproteinases during diapedesis. This process involves adhesion, proteolysis, and migration, enabling cells to reach infection sites without destroying the membrane.
Area of Science:
- Cell Biology
- Biochemistry
- Immunology
Background:
- Leukocyte extravasation is crucial for immune response.
- Basement membrane penetration by leukocytes is not fully understood.
Purpose of the Study:
- To investigate the mechanism of basement membrane penetration by polymorphonuclear leukocytes during diapedesis.
- To elucidate the role of proteolysis in leukocyte migration through basement membranes.
Main Methods:
- Scanning electron microscopy was used to visualize basement membrane changes.
- A Boyden chamber model with human amnion membrane simulated inflammatory conditions.
- Chemotactic gradient induced leukocyte migration.
Main Results:
- Leukocytes adhere to the basement membrane.
- Metalloproteinases, particularly gelatinase, mediate local proteolysis for penetration.
- Cells migrate through the membrane via active locomotion and squeezing, with minimal destruction.
- Type I collagen fibers in connective tissue are displaced without degradation.
Conclusions:
- Leukocyte diapedesis involves a three-step process: adhesion, proteolysis, and migration.
- Metalloproteinase-mediated basement membrane degradation facilitates leukocyte extravasation.
- Leukocytes can penetrate connective tissue barriers without complete matrix destruction.