Contact of migrating L5222 leukemia cells with the substrate as studied under the action of gravitational force

The interaction of actively migrating L5222 cells with the serum-coated glass surface was studied under the influence of an external force. In order to generate such force, the plane on which the cells were migrating, was inclined at different angles. The analysis of the L5222 cell migration pattern reveals that the modification of the cell movement direction relative to the surface appears when the plane is inclined at 1 degree. The increase of the slope to 2 degrees makes this effect more evident. When the slope is equal to 3 degrees the active motion of L5222 cells seems to disappear. The component of the gravitational force parallel to the plane on which the cells migrate ranges from 6.3 X 10(-15) N to 1.9 X 10(-14) N for the slopes from 1 degree to 3 degrees, respectively. The results of the study indicate that the force of interaction of migrating L5222 cells with the substrate is very small in comparison with the force of adhesion (not accompanied by locomotion) and seems to be comparable to that which operates in the near-substrate region of non-locomotive cells (e. g. L1210). Thus, the cell-substrate contact related to active movement and the non-locomotory adhesion of L5222 cells are probably different phenomena. As only L5222 cells were studied in this work, the above conclusions should be restricted to this cell type only.