Fractionation of mammalian bone marrow by counterflow centrifugation-elutriation using a continuous albumin gradient: analysis of granulocyte-macrophage colony-forming units.

Bone marrow cells from murine, canine, primate and human donors were fractionated by counterflow centrifugation-elutriation (CCE) using a continuous albumin gradient. Fractionation of 9 x 10(8) nucleated bone marrow cells (without prior removal of the erythrocytes) can be done in less than 1.5 h with 92% nucleated cell recovery, depending on donor species. Murine bone marrow cell recovery after fractionation averaged 52% whereas cell recoveries for canine, primate and human donors averaged 85%, 92% and 89%, respectively. The fractions were evaluated for total nucleated cell counts and granulocyte-macrophage colony-forming units (GM-CFC). Each species studied presented a unique profile for nucleated cell recovery and associated GM-CFC activity. These profile variations may suggest significant differences in the modes of GM-CFC expression in the individual species that may depend on cell-to-cell interactions. Although CCE is unable to isolate a single population responsible for GM-CFC activity, CCE does permit a rapid, reproducible fractionation of a large numbers of cells with minimal manipulation of sample. This makes the isolated sample ideal for further purification of progenitor cell populations