Isokinetic gradient sedimentation of normal human bone marrow cells: a simple method for isolation of proliferative granulocytic and erythroid elements.

Proliferative granulocytes and erythroid precursors were isolated from cell suspensions of human normal bone marrow by sedimentation on an isokinetic gradient of continuous low-density Ficoll. A fivefold enrichment with a 70% recovery of the proliferative granulocyte cohort and of early erythroid elements was achieved, as determined by differential morphology and tritiated thymidine incorporation. Viability and in vitro proliferative capacity following gradient centrifugation remained intact. This method of cell separation, based on differences in cell diameter, affords a simple and rapid means for the purification of specific cell populations from heterologous human normal bone marrow.