A developing picture of lymphopoiesis in bone marrow

• Published in: Immunological reviews 2002-11, Vol.189 (1), p.28-40
• Main Authors: Hirose, Jun, Kouro, Taku, Igarashi, Hideya, Yokota, Takafumi, Sakaguchi, Nobuo, Kincade, Paul W.
• Format: Article
• Language: English
• Subjects: Animals; Antigens, CD19 - metabolism; B-Lymphocytes - cytology; B-Lymphocytes - immunology; Biological and medical sciences; Bone Marrow - anatomy & histology; Bone Marrow Cells - cytology; Bone Marrow Cells - immunology; Bone Marrow Cells - metabolism; Carrier Proteins - metabolism; Drosophila Proteins; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Green Fluorescent Proteins; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - immunology; Hematopoietic Stem Cells - metabolism; Homeodomain Proteins - metabolism; Humans; Immunobiology; Killer Cells, Natural - cytology; Killer Cells, Natural - immunology; Leukocyte Common Antigens - metabolism; Luminescent Proteins - genetics; Lymphoid cells: ontogeny, maturation, markers, receptors, circulation and recirculation; Lymphopoiesis - immunology; Lymphopoiesis - physiology; Mice; Mice, Transgenic; Models, Immunological; Proto-Oncogene Proteins c-kit - metabolism; T-Lymphocytes - cytology; T-Lymphocytes - immunology
• ISSN: 0105-2896; 1600-065X
• DOI: 10.1034/j.1600-065X.2002.18904.x

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.