Abstract: A method for identifying activated T-cells from naive T-cells using a moving optical gradient comprises the steps of providing a sample of cells containing T-cells, moving the cells and the optical gradient relative to each other so as to cause displacement of at least some of the cells, measuring the displacement of at least a portion of the displaced cells, and comparing the measured displacement of the T-cells with a known measured displacement of naive T-cells. The method can also be used to identify T-cell activating agents.

Abstract: A diagnostic method for determining whether a suspect cell is cancerous using an optical gradient includes the steps of moving the suspect cell and the optical gradient relative to each other so as to cause displacement of the cell, measuring the displacement of the cell, comparing the measured displacement of at least one non-cancerous control cell. The step of comparing the measured displacement of the suspect cell and the at least one non-cancerous control cell determines whether the suspect cell is cancerous. The method can also be used to identify cancerous cells in a sample by identifying those cells having the largest measured displacements as a result of the relative movement between the cells and the optical gradient.