A developing picture of lymphopoiesis in bone marrow.
The earliest progenitors of lymphocytes are extremely rare and typically present among very complex populations of hematopoietic cells. Additionally, it is difficult to know how cells with any given set of characteristics are developmentally related to stem cells and maturing lymphoid precursors. However, it is now possible to divide bone marrow into progressively smaller fractions and exploit well-defined culture systems to determine which ones contain cells that can turn into lymphocytes. Analysis of steroid hormone sensitive cells and use of two-step cultures is providing additional information about the most likely differentiation pathways for B and natural killer cell lineage lymphocytes. A newly identified category of early lymphoid progenitors can now be sorted to high purity from RAG1/GFP knock in mice. Furthermore, the same experimental model makes it possible to image lymphoid progenitors in fetal and adult hematopoietic tissues.
Hirose
Jun
J
Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
Kouro
Taku
T
Igarashi
Hideya
H
Yokota
Takafumi
T
Sakaguchi
Nobuo
N
Kincade
Paul W
PW
D000818:Animals; D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D001853:Bone Marrow / Q000033:anatomy & histology; D001854:Bone Marrow Cells / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D029721:Drosophila Proteins; D049452:Green Fluorescent Proteins; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics; D038041:Lymphopoiesis / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D018448:Models, Immunological; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology
D018941:Antigens, CD19; D002352:Carrier Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; C410902:lin protein, Drosophila; C064658:RAG-1 protein; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit; D017493:Leukocyte Common Antigens