The goal of the proposed research is the development of electrophoretic light scattering (ELS) for the automated electrophoretic analysis of suspensions of living cells and the application of this method to problems of biophysical and medical significance. We have demonstrated that ELS can be used to distinguish the electrophoretic properties of T and B lymphocytes and to distinguish both types of normal cells from peripheral blood lymphoblasts of patients with acute lymphocytic leukemia. It is proposed to pursue these experiments and to employ ELS for clinical evaluation of patients in the course of treatment. The relationship between cell surface charge and cell adhesion will be studied in a series of experiments on mouse fibroblasts. The effects of leukocyte inhibition factor (LIF) and macrophage inhibition factor (MIF) on the cell agglutinability and surface charge density of polymorphonuclear leukocytes and macrophages, respectively, will be determined. ELS will be applied to the development of the macrophage electrophoretic mobility (MEM) test for the detection of neoplastic disorders. The surface charge and charge reactions of blood platelets will also be studied. Corroborative experiments will be carried out on various biosurfaces using streaming potential measurements.