Stimulation and inhibition of human granulopoiesis in vitro by normal and malignant T4- or T8-lymphocyte subpopulations.
We studied the role of total peripheral blood T-lymphocytes and separated subpopulations of OKT4+ and OKT8+ cells stimulated with concanavalin A in the regulation of human granulopoiesis. Unfractionated total T cells depleted of monocytes are capable of producing colony-stimulating activity (CSA) and colony-forming unit-clone (CFU-C) suppressor activity simultaneously. After positive selection of cell subsets using a fluorescence-activated cell sorter, these two activities were produced by OKT4+ lymphocytes, whereas OKT8+ cells displayed small amounts of CSA and were incapable of releasing suppressor activity. On the other hand, total human thymocytes and subsets defined by monoclonal antibodies Leu2a/Leu3a failed to express any detectable CSA or CFU-C suppressor activity. A total of 14 cases of phenotyped lymphoid malignancies were also studied: the results showed that the production of stimulating and/or inhibiting factors is neither clearly related to a discrete stage of differentiation nor to the OKT4/OKT8 phenotype. Moreover, three monoclonal T leukemias, OKT4+OKT8-, OKT4-OKT8-, and OKT4-OKT8+ have been able in each case to produce simultaneously CSA and CFU-C suppressor activity. Finally, these studies strongly suggest that the activities of T-lymphocytes involved in the regulation of granulopoiesis are not closely linked with OKT4/OKT8 phenotype.
D002448:Cell Adhesion; D002450:Cell Communication / Q000187:drug effects; D002460:Cell Line; D002648:Child; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000378:metabolism; D003208:Concanavalin A / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology*; D006410:Hematopoiesis / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007694:Killer Cells, Natural / Q000502:physiology; D007945:Leukemia, Lymphoid / Q000276:immunology / Q000503:physiopathology; D008213:Lymphocyte Activation / Q000187:drug effects; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000502:physiology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000502:physiology*
D003115:Colony-Stimulating Factors; D003208:Concanavalin A