A procedure for the quantitative separation of viable and non-viable P815X2 mastocytoma cells

A method for the separation of viable and non-viable P815X2 mastocytoma cells is described using Ficoll discontinuous density gradients. Non-viable P815X2 cells are more dense than viable P,15X2 cells and reach a bouyant density equilibrium at a higher Ficoll concentration than the viable cells. This technique allows the separation of viable P815X2 cells from cells that had been killed by antiserum and complement, or by non-growth supporting medium or by cytotoxic lymphocytes. This method is a new assay to determine cytotoxic lymphocyte killing of P815X2 cells.