Single tether formation from unstimulated microvascular endothelial cells

Endothelial cells are actively involved in recruitment of leukocytes through receptor mediated cell adhesion. Previous studies indicate that tether formation is vital to a sustained receptor-ligand interaction subject to shear stresses encountered under physiological conditions. However, limited information exists on the contribution of membrane properties of these cells towards a stable rolling interaction with leukocytes. We therefore propose to estimate the intrinsic tether force (F₀) and membrane viscosity (η_eff) for single tether formation from attached and suspended unstimulated microvascular endothelial cells (MECs) using anti-CD29 and anti-CD31 antibody-coated beads. The analysis predicts a linear relationship between the tether force and velocity as has been shown previously. Further, comparable estimates of the intrinsic parameters (F₀ and η_eff) using anti-CD31 and anti-CD29 coated beads also support the hypothesis that tether formation from MECs is independent of the surface receptor type.