Effects of harvesting methods on neutrophil yields in the ES/OP9 coculture system. Cells from day 9 in the neutrophil differentiation mix were either gently or thoroughly harvested, as described in “Materials and methods,” at the indicated times. For this figure, the data are expressed as the total number of bands to polysegmented neutrophils recovered by gentle harvesting or by thorough harvesting. In addition, the number of cells remaining associated with the stroma after thorough harvesting is indicated. Error bars represent standard deviations.