AN ADHESION ASSAY USING MINIMAL SHEAR FORCE TO REMOVE NONADHERENT CELLS

A new 96-well microtiter plate based adhesion assay was developed to m easure weak cell adhesion. This assay is distinct from other adhesion assays by the procedure in which the nonadherent cells are removed. In most conventional adhesion assays, nonadherent cells are removed by a spiration followed by repeated washes. However, the shear force genera ted by such washing also detaches weakly adherent cells. In the minima l shear force adhesion assay (MSFA) described here, the removal of non adherent cells is carried out by applying a gentle shear force in a fl uid environment. In this procedure, adherent cells are not subjected t o harsh and variable washing forces and are not exposed to surface ten sion caused by the removal of washing fluid between successive washes. Using the lymphoid cell lines XC1.5/51 and MPC11, the number of adher ent cells determined by this new adhesion assay is three times higher than the conventional adhesion assay. This MSFA assay is simple, consi stent, and easy to perform. With modifications for applying a defined shear force, this assay can be adopted to compare cell adhesion streng th to various substrata.