title: Regulation of granulocyte and macrophage colony-stimulating factor production by phytohaemagglutinin-treated blood mononuclear cells.
abstract: The colony-stimulating activity (CSA) of medium conditioned by phytohaemagglutinin (PHA)-stimulated blood mononuclear cells was tested using granulocyte-macrophage colony-forming cells (GM-CFC) from normal bone marrow. Low concentrations of the conditioned medium stimulated granulocytic colony-forming cells (CFC) which formed colonies by the seventh day of incubation; higher concentrations stimulated the formation of macrophage colonies which were not seen until the end of the second week in culture. The colony-stimulating activities could not be demonstrated in adherent cell-depleted bone marrow cultures. This dependence of activity on adherent cells was confirmed by incubating different concentrations of conditioned medium with isolated adherent cells and then testing for colony-stimulating activity in cultures of non-adherent bone marrow cells. The activities of conditioned media following exposure to adherent cells corresponded to the results seen when the conditioned medium from PHA-stimulated mononuclear cell cultures was used to stimulate agar cultures of unseparated marrow. The results suggest that PHA-responsive mononuclear cells (probably T lymphocytes) may modulate the regulation of colony-stimulating factor (CSF) production by adherent colony-stimulating cells (CSC).
mesh_terms: D002448:Cell Adhesion; D003115:Colony-Stimulating Factors / Q000378:metabolism*; D003470:Culture Media; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000166:cytology; D009000:Monocytes / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D003115:Colony-Stimulating Factors; D003470:Culture Media; D010835:Phytohemagglutinins