Electrophoretic separation and analysis of living cells from solid tissues by several methods. Human embryonic kidney cell cultures as a model.

Preparative electrophoresis of living cells has been considered for some time as a potential tool for isolating, from heterogeneous mixtures, subpopulations of cells according to function. Such a purification depends upon the retention of electrophoretic heterogeneity and the retention of function. Human embryonic kidney cells that had been in monolayer culture for 1-5 subcultivations were resuspended by treatment with trypsin and/or EDTA and suspended in a variety of electrophoresis buffers, ranging in ionic strength from 0.0015 to 0.15 M. Analytical electrophoresis with a Zeiss Cytopherometer or Pen Kem 3000 automated light-scattering electrophoretic analyzer indicated that electrophoretic heterogeneity was retained under the full range of conditions tested. Preparative electrophoresis by three methods--in a density gradient, with continuous flow, and in microgravity--indicated that electrophoretic heterogeneity coincided with functional heterogeneity; for example, some electrophoretically isolated subpopulations produced increased levels of urokinase while others produced increased level of tissue plasminogen activator.