title: Differential ability of flt3-ligand, interleukin-11, and Steel factor to support the generation of B cell progenitors and myeloid cells from primitive murine fetal liver cells.
abstract: A variety of factors produced by stromal fibroblasts, including Flt3-ligand (FL), interleukin-11 (IL-11), Steel factor (SF), and IL-7, have been implicated in stimulating the production of pre-B cells and myeloid cells from primitive hematopoietic precursors. To investigate their relative roles in this process, either as single-acting or synergistic agents, we compared the yield and types of cells produced after 2 weeks from small numbers of Sca-1+ Lin- (i.e., B220-, Ly-1-, Gr-1-, and Ter-119-) day 14.5 murine fetal liver cells placed in stromal cell-free cultures containing all possible combinations of FL, SF, IL-7, and IL-11. None of these factors alone supported the production (or survival) of any cells beyond 1 week: only pairs of factors consisting of either FL or SF plus either IL-11 or IL-7 were effective in this regard, with FL plus IL-11 being the most potent pair (approximately 7 x 10(4) cells obtained per 100 Sca-1+ Lin- input cells). The maximum numbers of cells were produced in the presence of FL, IL-11, and IL-7: these included both B220+ and Mac-1+/Gr-1+ cells (approximately 10(6) and approximately 2 x 10(5), respectively, per 100 Sca-1+ Lin- input cells). Both of these lineages were also obtained with each of the other possible three-factor combinations, albeit with variable effectiveness. Omission of either FL or IL-7 caused the greatest reduction in the yield of B220+ cells (approximately 130-fold and approximately 80-fold, respectively). Omission of IL-11 and, to a lesser extent, FL caused the greatest reduction in the yield of Mac-1+/Gr-1+ cells (approximately 90-fold and approximately 3-fold, respectively). When fetal calf serum was replaced with a defined serum substitute, the out put of B220+ cells remained the same but myelopoiesis was consistently enhanced (approximately 5- to 20-fold). These findings support a model involving factor redundancy in the extracellular signals required to stimulate the production and amplification of both lymphoid and myeloid cells from early Sca-1+ Lin- cells. They also reveal quantitative differences in the abilities of different competent factor combinations to promote this process, which may be further modulated by the presence of undefined serum components.
authors.affiliation: British Columbia Cancer Agency, and Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Lemieux
authors.forename: S M
authors.initials: SM
authors.lastname: Chappel
authors.forename: C L
authors.initials: CL
authors.lastname: Miller
authors.forename: C J
authors.initials: CJ
authors.lastname: Eaves
mesh_terms: D000818:Animals; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000166:cytology*; D001769:Blood; D002454:Cell Differentiation; D006098:Granulocytes / Q000166:cytology*; D006133:Growth Substances / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D017370:Interleukin-11 / Q000494:pharmacology*; D051917:Leukosialin; D008099:Liver / Q000166:cytology / Q000196:embryology*; D008565:Membrane Proteins / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D012795:Sialoglycoproteins / Q000032:analysis; D019089:Stem Cell Factor / Q000494:pharmacology*
chemical_list: D015703:Antigens, CD; D006133:Growth Substances; D017370:Interleukin-11; D051917:Leukosialin; D008565:Membrane Proteins; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D019089:Stem Cell Factor; C084881:flt3 ligand protein