title: Promotion of hematopoietic stem cell differentiation in vitro by a soluble mediator, allogeneic effect factor.
abstract: This study was designed to investigate the effects of allogenic effect factor (AEF), a soluble mediator derived from short-term mixed lymphocyte cultures (MLC) of in vitro alloantigen-primed T cells, on cultures of murine bone marrow cells. Cultures established under suboptimal conditions namely, in the absence of a pre-established adherent cell layer as required in conventional Dexter-type cultures--declined and lost their stem cell activity rapidly. In contrast, supplementation of these cultures, at initiation and thereafter, with AEF, but not with T cell growth factor (TCGF), induced cell growth and proliferation for several weeks. Such AEF-supplemented cultures exhibited cellular heterogeneity and stem cell activity for significantly longer periods than the control cultures. Even in conventional Dexter cultures, established under optimal conditions, AEF had a beneficial effect on cellular growth and proliferation and myeloid progenitor cell (CFU-C) activity. Furthermore, cell capable of synergizing with suboptimal numbers of mature T cells in con A-induced mitogenic responses, shown by others to be pre-T cells, were detected in the AEF-supplemented cultures for several weeks.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000502:physiology; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003208:Concanavalin A; D004261:DNA Replication; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D008222:Lymphokines; C022780:allogenic effect factor; D003208:Concanavalin A