INFLUENCE OF ADHESIVE BOMBS AND SURFACE RUGOSITY ON THE INTERACTION BETWEEN RAT THYHOCYTES AND FLAT SURFACES UHDEK LAMINAR SHEAR FI.OW

Abstract Many functions of blood leukocytes or platelets are dependent on their ability to stick to endothelial walla under flou conditions, fluch experimental evidence suggests that the efficiency of attachment, of cells moving along a flat surface is negatively correlated to their translational velocity. In the present uork, ue describe the motion of rat thymocytes falling on a plastic coverslip in a laminar shear flou. The Importance of cell surface roughness was studied by smoothing thymocytes in hypotonic media with electron microscopic monitoring. The effect of adhesive interactions uas tested hy coating coverslips with concanavalin A. Also, the importance of cell rigidity uas investigated by studying the influence of paraformaldehyde fixation on adhesion. Results are consistent with the view that cells behave as rigid bodies separated from the surface by a liquid film thicker than 135 nanometers. Adhesions would thus be initiated by transient decreases of the cell-surface gap. Further studies are