title: Direct evidence for the commitment of hematopoietic stem cells to T, B and myeloid lineages in murine fetal liver.
abstract: We established an experimental system in vitro to examine the developmental capacity of individual hematopoietic progenitors to generate T, B and myeloid (M) cells. By using this system we analyzed the process of lineage commitment of hematopoietic progenitors in murine fetal liver (FL). It is known that small numbers of B and M cells, in addition to T cells, are generated in a co-culture of hematopoietic progenitors and a deoxyguanosine-treated fetal thymus (FT) lobe. We tried to enhance the growth of B and M cells by the addition of IL-7, IL-3 and stem cell factor into the co-culture. This cytokine-supplemented FT organ culture was used to examine the developmental capacity of individual hematopoietic progenitors in FL. Single cells of lineage marker (Lin)-c-kit+Sca-1+ (Sca-1+) and Lin-c-kit+Sca-1-(Sca-1-) populations from the FL harvested at day 12 of gestation were cultured for 10 days, and the phenotypes of cells generated in each lobe were analyzed with a flow cytometer. All progenitors in the Sca-1- population were shown to be committed to generate only T, B or M cells. On the other hand, multipotent progenitors, which are capable of generating T, B and M cells, as well as unipotent progenitors committed to the T, B or M lineage were found in the Sca-1+ population. Bipotent progenitors generating M and T cells and those generating M and B cells were also found in the Sca-1+ population, which probably represent progenitors in the process of commitment. However, no bipotent progenitors generating T and B cells were detected.
authors.affiliation: Department of Immunology, Chest Disease Research Institute, Kyoto University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawamoto
authors.forename: K
authors.initials: K
authors.lastname: Ohmura
authors.forename: Y
authors.initials: Y
authors.lastname: Katsura
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000032:analysis; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D001853:Bone Marrow / Q000276:immunology / Q000378:metabolism; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000276:immunology; D002999:Clone Cells; D016207:Cytokines / Q000494:pharmacology; D005333:Fetus / Q000166:cytology / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008099:Liver / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism
chemical_list: D000950:Antigens, Ly; D016207:Cytokines; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D019009:Proto-Oncogene Proteins c-kit; D017493:Leukocyte Common Antigens