Diversity of human granulopoietic precursor cells: separation of cells that form colonies in diffusion chambers (CFU-d) from populations of colony-forming cells in vitro (CFU-c) by velocity sedimentation

Abstract

Normal human bone marrow contains cells that form granulocytic colonies in fibrin clot diffusion chambers implanted intraperitoneally in sublethally irradiated mice (CFU-d). A series of experiments was performed to determine the relationship between CFU-d and the cells that form colonies in agar culture in vitro (CFU-c). Low-density bone marrow cells ( 3 ) were separated by velocity sedimentation and colony-forming cells in each fraction assessed by culture in diffusion chambers and in soft agar. CFU-d sedimented more slowly than the vast majority of CFU-c, with a peak sedimentation velocity of 5.0 ± 0.4 mm/hr. Two different CFU-c populations could be distinguished. One was a rapidly sedimenting cell population (7.3 ± 0.9 mm/hr.) that formed colonies after 1 wk incubation in vitro. On day 14, however, colonies were derived from more slowly sedimenting cells that had a peak sedimentation velocity of 6.0 ± 0.5 mm/hr. Clusters (3-50 cells), scored on day 7 in agar ##