Neutrophil Adhesive Contact Dependence on Impingement Force

• Published in: Biophysical journal 2004-12, Vol.87 (6), p.4237-4245
• Main Authors: Spillmann, C.M., Lomakina, E., Waugh, R.E.
• Format: Article
• Language: English
• Subjects: Cell adhesion & migration; Cell Adhesion - physiology; Cell Adhesion Molecules - metabolism; Cell Biophysics; Cells; Cells, Cultured; Humans; Image Interpretation, Computer-Assisted - methods; Intercellular Adhesion Molecule-1 - metabolism; Leukocytes; Magnesium; Mechanotransduction, Cellular - physiology; Membrane Fusion - physiology; Micromanipulation - methods; Neutrophils - cytology; Neutrophils - physiology; Physical Stimulation - methods; Protein Binding; Stress, Mechanical
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1529/biophysj.103.031773

Neutrophil capture and recruitment from the circulation requires the formation of specific receptor/ligand bonds under hydrodynamic forces. In the present study we examine bond formation between β 2-integrins on neutrophils and immobilized ICAM-1 while using micropipettes to control the force of contact between the cell and substrate. Magnesium was used to induce the high affinity conformation of the integrins, and bond formation was assessed by measuring the probability of adhesion during repeated contacts. Increasing the impingement force caused an increase in the contact area and led to a proportional increase in adhesion probability (from ∼20 to 50%) over the range of forces tested (50–350 pN). In addition, different-sized beads were used to change the force per unit area in the contact zone (contact stress). We conclude that for a given contact stress, the rate of bond formation increases linearly with contact area, but that increasing contact stress results in higher intrinsic rates of bond formation.