Separation of human bone marrow cell populations by density gradient electrophoresis: Differential mobilities of myeloid (CFU-C), monocytoid, and lymphoid cells

Abstract

Human bone marrow cells from normal donors (purified by centrifugation on Ficoll-Hypaque density cushion) were separated by density gradient electrophoresis, on the basis of their surface charge. The separated cell fractions were analyzed by morphology, surface markers, and functional tests. Morphological examination revealed that immature cells of myeloid and erythroid lineage were significantly enriched in the high-mobility fractions, whereas mature cells in general, e.g., small lymphocytes, monocytes and granulocytes (few) were highly enriched in the low-mobility fractions. Ripley rosette-forming cells, as well as complement receptor and Fc (IgG)-receptor-bearing lymphocytes were relatively enriched in the high-mobility fractions, although they were present in small proportions and in the rest of the fractions. E-rosette-forming cells were enriched in the intermediate- and low-mobility fractions. T cells with Fc receptors for IgM (Tμ cells), determined by a double-rosetting technique, were found to be enriched in the intermediate-mobility fractions. In contrast T cells with Fc receptors for IgG (Tγ cells) were significantly enriched in the low-mobility fractions. Cells in the intermediate-mobility fractions (Tμ enriched) responded by proliferation to mitogens and to allogeneic cells in mixed lymphocyte culture. Cells in the very high or very low (Tγ enriched) mobility fractions responded poorly. Colony-forming units in vitro (CFU-C), determined using either the human leukocyte feeder or the placental CSA culture systems, were found to be significantly enriched in the high-mobility fractions. Low-mobility fractions were devoid of CFU-C. These studies demonstrate that density gradient electrophoresis can be successfully applied for the separation of human bone marrow cells of different lineage and studies of their functional properties.