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Quantifying rolling adhesion with a cell-free assay: E-selectin and its carbohydrate ligands
1School of Chemical Engineering, Cornell University, Ithaca, New York 14853, USA.
Biophysical Journal
|June 1, 1997
Summary
Neutrophil rolling on endothelial cells, crucial for inflammation, depends on selectin-carbohydrate interactions. This study quantifies rolling dynamics, finding velocity is sensitive to E-selectin and sialyl Lewis(x) density and shear stress.
Area of Science:
- Immunology
- Biophysics
- Cell Biology
Background:
- Neutrophil rolling on endothelial cells is a critical early step in inflammatory responses.
- Selectin adhesion molecules mediate this rolling by binding to carbohydrate ligands like sialyl Lewis(x).
Purpose of the Study:
- To quantitatively describe the adhesion dynamics of a cell-free rolling system using E-selectin and sialyl Lewis(x)-coated microspheres.
- To investigate the influence of receptor/ligand density, shear stress, and carbohydrate chemistry on rolling velocity.
Main Methods:
- Utilized a cell-free system with E-selectin-IgG chimera substrates and sialyl Lewis(x)-coated microspheres.
- Performed quantitative analysis of particle rolling velocity under varying conditions.
Main Results:
- Rolling velocity increased with wall shear stress and decreased with higher E-selectin or sialyl Lewis(x) densities.
- Rolling velocity was more sensitive to E-selectin surface coverage than sialyl Lewis(x) density.
- Carbohydrate effectiveness followed the trend: sialyl Lewis(a) > sialyl Lewis(x) >> sulfated Lewis(x) >> Lewis(x).
- Velocity fluctuations were linearly proportional to mean rolling velocity.
Conclusions:
- The cell-free system accurately mimics leukocyte rolling dynamics.
- E-selectin and sialyl Lewis(x) densities, along with shear stress, are key regulators of rolling velocity.
- Carbohydrate structure significantly impacts selectin-mediated rolling efficiency.