title: The production of granulocyte-monocyte colony-stimulating activity by isolated human T lymphocyte subpopulations.
abstract: Isolated human T lymphocyte subpopulations were obtained by fluorescence-activated cell sorting using the murine monoclonal antibodies, OKT4 and OKT8. The capabilities of the isolated lymphocytes to produce granulocyte-monocyte colony-stimulating activity (CSA) in response to mitogen challenge were assessed by in vitro assays employing light density nonadherent bone marrow cells. Essentially, no CSA production was noted by any isolated T lymphocyte population [OKT4 positive (+) or OKT8 positive (+)] cultured alone or following the addition of 10(4) autologous monocytes/ml. When phytohemagglutinin (PHA) alone was added, OKT4+ lymphocytes elaborated small amounts of CSA. With the addition of concanavalin A (Con-A) alone, both OKT4+ and OKT8+ cells were able to produce modest amounts of CSA. Significantly enhanced CSA production was observed when either OKT4+ or OKT8+ lymphocytes were coincubated with autologous monocytes in the presence of mitogen. We conclude that highly purified T lymphocyte subpopulations, free of monocytes as assessed by nonspecific esterase staining, can elaborate small amounts of CSA in response to PHA or Con-A challenge. A synergistic augmentation of CSA production was noted with coincubation of sorted lymphocytes and autologous monocytes in the presence of mitogen. Finally, our results suggest that the ability of T lymphocytes to make CSA is not exclusively limited to either the OKT4+ or OKT8+ defined subsets.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D002469:Cell Separation; D003115:Colony-Stimulating Factors / Q000096:biosynthesis* / Q000502:physiology; D006098:Granulocytes / Q000166:cytology; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008934:Mitogens / Q000494:pharmacology; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D003115:Colony-Stimulating Factors; D008934:Mitogens