Inhibitory effect of PWM-stimulated OKT4+ subsets on erythro-, granulo- and megakaryocytopoiesis in vitro.
Normal human peripheral blood T cells and T-cell subsets defined by monoclonal antibodies of the OKT series were pretreated with pokeweed mitogen (PWM). Their effects on the haematopoietic precursors, erythroid (BFU-E, CFU-E), granulocyte-macrophage (CFU-GM) and megakaryocyte (CFU-M) colony forming cells were evaluated by coculture. While unstimulated T cells and T-cell subsets enhanced growth of autologous blood BFU-E, PWM-stimulated T and OKT4+ cells suppressed it, also inhibiting proliferation of both autologous and allogeneic bone marrow BFU-E, CFU-E, CFU-GM and CFU-M. PWM-stimulated OKT8+ cells had little effect on the growth of any of the precursors at the cell concentration at which growth was completely inhibited by PWM-stimulated OKT4+ cells. Irradiation of T or OKT4+ cells with 3000 rad before PWM stimulation completely abrogated the inhibition. These observations might be related to the mechanism of pancytopenia in some cases of immune-mediated aplastic anaemia.
D000911:Antibodies, Monoclonal; D002455:Cell Division; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D004306:Dose-Response Relationship, Immunologic; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D008213:Lymphocyte Activation; D011043:Pokeweed Mitogens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D011043:Pokeweed Mitogens