title: Modulation of in vitro myelopoiesis by LGL: different effects on early and late progenitor cells.
abstract: We describe here the modulatory activity of human peripheral blood natural killer (NK) cells on the growth and differentiation of myeloid progenitor cells at different stages of maturation. NK-enriched cell fractions containing 54 to 75% large granular lymphocytes (LGL) and displaying high levels of NK activity significantly inhibited the growth of late (7 day) granulocyte-macrophage colony-forming cells (CFU-GM) from about 50% of normal human bone marrow samples. However, the same fractions strongly enhanced the growth of early (14 day) stem cells from peripheral blood. Enhancing activity on early CFU-GM from blood was greater in highly purified NK cell preparations containing 96% LGL than in NK-depleted T cell preparations from the same donors. Analogous to the results when using the NK-enriched fractions, the NK-purified preparations inhibited late CFU-GM and stimulated the early ones. We conclude from these observations that human LGL have a modulatory effect on myelopoiesis depending on the maturation stage of the progenitor cell.
mesh_terms: D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002455:Cell Division; D002469:Cell Separation; D003114:Colony-Forming Units Assay; D003602:Cytotoxicity, Immunologic; D006098:Granulocytes / Q000276:immunology / Q000502:physiology; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008215:Lymphocytes, Null / Q000276:immunology / Q000502:physiology; D008264:Macrophages / Q000276:immunology / Q000502:physiology; D013997:Time Factors