| Abstract: | Multipotential hematopoietic progenitor cell lines have been established from nonadherent cell populations removed from continuous mouse bone marrow cultures. Clonal sublines of lines B6SUtA or B6JUt derived from single cells formed mixed colonies containing erythroid cells, neutrophil-granulocytes, and basophil/mast cells in semisolid medium containing erythropoietin and conditioned medium from pokeweed mitogen-stimulated spleen cells. Each of several subclones of cell line Ro cl formed colonies containing eosinophils, neutrophil-granulocytes, and basophil/mast cells in semisolid medium. Multipotentiality was maintained in vitro for over 2 1/2 years. In contrast, cell line 32D formed basophil/mast cell colonies with no detectable differentiation to other pathways. Multipotential cell lines did not produce detectable spleen colonies (CFUs) in vivo, nor did intravenous inoculation of up to 5 X 10(7) cells protect lethally irradiated mice from bone marrow failure. Newborn and adult mice inoculated with 5 X 10(7) cells showed no detectable leukemia or solid tumors after one year. Both multipotential and committed basophil/mast cell lines demonstrated absolute dependence upon a source of a growth factor(s) found in medium conditioned by WEHI-3 cells. These cell lines should be of value in studies of the regulation of hematopoietic stem cell differentiation in vitro. |
