Haemopoietic progenitor cell differentiation: flow cytometric assessment in bone marrow and thymus.
We have recently shown that expression of any of the lineage-associated molecules CD2, CD7, CD10, CD19 or CD33 does not ensure lineage-commitment of CD34+ progenitor cells. Further, normal progenitor cells and leukaemic blast cells have been shown to coexpress molecules associated with more than one haemopoietic lineage. Five-dimensional flow cytometric analysis of normal bone marrow cells was exploited to investigate the hypothesis of a developmental stage in haemopoiesis comprising CD34+ cells coexpressing CD2, CD5, CD7, CD10, CD19 and CD33 or any combination of these molecules. We report on a subpopulation of CD34+ bone marrow cells constituting < 5% of the CD34+ cells and characterized by extensive coexpression of several molecules associated with the B lymphoid, T lymphoid and myeloid lineages. There is every probability that some cells display the CD34+ CD2+ CD5+ CD7+ CD10+ CD19+ CD33+ phenotype. Studies on postnatal thymocytes suggest that this may be the phenotype or one of a few phenotypes of a candidate thymus-seeding progenitor cell population. Finally, our findings that CD34+ as well as CD34+ CD5+ thymocytes can be driven into non-T-lymphoid differentiation by cytokines, support the notion that the thymus is seeded by uncommitted progenitors.
Tjønnfjord
G E
GE
Institute of Transplantation Immunology, National Hospital, University of Oslo, Norway.
Steen
R
R
Veiby
O P
OP
Mørkrid
L
L
Egeland
T
T
D000328:Adult; D015703:Antigens, CD; D018941:Antigens, CD19; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D018801:CD2 Antigens; D002454:Cell Differentiation / Q000502:physiology; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000502:physiology*; D006801:Humans; D063268:Sialic Acid Binding Ig-like Lectin 3; D013601:T-Lymphocytes / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
D015703:Antigens, CD; D018941:Antigens, CD19; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; D018801:CD2 Antigens; C571163:CD33 protein, human; D063268:Sialic Acid Binding Ig-like Lectin 3