title: Stimulation of human BFU(E) by products of human monocytes and lymphocytes.
abstract: Regulation of normal human peripheral blood BFU(E) by lymphocytes and monocytes was investigated using plasma clot cultures. Monocyte depletion from peripheral blood mononuclear cells (MNC) resulted in 28 to 98% inhibition of BFU(E) growth in 16 of 17 experiments, but T lymphocyte depletion caused no decrease in BFU(E). When both T cells and monocytes were removed there was an 80% decrease in BFU(E) growth. Addition of as few as 10(4) monocytes alone increased BFU(E) to 88% of expected levels, but addition of 5 x 10(4) T lymphocytes resulted in an increase to only 57% of anticipated BFU(E) numbers. Conditioned media (CM) from 5 x 10(5) to 10(6) unstimulated T lymphocytes per ml stimulated BFU(E) growth from cultures of non-adherent cells, but not from cultures of T cell depleted MNC. Monocyte CM produced peak (2.2-fold) stimulation with only 10(5) monocytes/ml. CM from 5 x 10(5) to 10(6) monocytes/ml had no detectable erythroid burst promoting activity (BPA). Thus, unstimulated monocytes produce BPA, and at high cell concentrations, also produce a presumed inhibitor of BPA production or biologic activity. Although T cells may play some role in control of BFU(E), monocytes appear to be critical for optimal BFU(E) growth in vitro.
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Simpson Memorial Research Institute, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Zuckerman
mesh_terms: D002478:Cells, Cultured; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D017077:Culture Media, Conditioned / Q000378:metabolism; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D047589:Leukocyte Reduction Procedures; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology*; D009000:Monocytes / Q000166:cytology / Q000502:physiology*
chemical_list: D017077:Culture Media, Conditioned