IN-VITRO SIDE-VIEW IMAGING TECHNIQUE AND ANALYSIS OF HUMAN T-LEUKEMICCELL-ADHESION TO ICAM-1 IN SHEAR-FLOW

The objective of the present study is to apply a novel side-view imagi ng technique to investigate T-leukemic Jurkat cell adhesion to a surfa ce-immobilized ICAM-1 in shear now, a ligand for leukocyte LFA-1. Imag es have revealed that Jurkat cell adhesion on ICAM-1 under now conditi ons in vitro is quasistatic. The cell-substrate contact length steadil y increased with time during the initial cell attachment to the ICAM-1 -coated surface and subsequently decreased with time as the trailing e dge of the cell membrane peeled away from the substrate under the infl uence of fluid shear forces. Changes in now shear stresses, cell defor mability, or substrate ligand strength resulted in a significant chang e in the characteristic adhesion binding time and contact length. A 3- D now field with shear stresses acting on an adherent cell was calcula ted by using finite element methods based on cell shapes obtained from the in vitro images. The maximum shear stress acting on an actual cel l body was found to be 3-5 times greater than the upstream inlet wall shear stress and was influenced by the extent of cell deformation with in the flow channel. Therefore, the application of such a side-view im aging technique has provided a practical assay to study the mechanics of cell-surface adhesion in 3-D. The elongation of cells in shear flow tempers hydrodynamic shear forces on the cell, which affects the tran sients in cell-surface adhesion, (C) 1998 Academic Press.