Modulation of in vitro eosinophil progenitors by hydrocortisone: role of accessory cells and interleukins.
The growth of human eosinophil progenitors (CFU-Eo) and the modulation of growth by hydrocortisone were studied as functions of the presence of lymphocytes and monocytes in marrow cells under study; and the source of colony-stimulating factors, specifically, media conditioned by macrophage-like cell line, GCT; phytohemagglutinin-stimulated mononuclear cells (PHA-LCM); or the T cell line, MO. CFU-Eo growth was greatest in marrow containing accessory cells as compared to marrow depleted of accessory cells; and in marrow treated with phytohemagglutinin-stimulated leukocyte conditioned media (PHA-LCM) or MO (T cell line)-conditioned medium (MO-CM) as compared with GCT cell-conditioned medium (GCT-CM). Hydrocortisone reproducibly inhibited eosinophil progenitor growth in unfractionated marrow stimulated by GCT-CM. This effect was abrogated by admixing irradiated mononuclear cells or T lymphocytes with the target marrow or by adding interleukin 1 or interleukin 2 (IL-1, IL-2). Inhibition by hydrocortisone did not occur when monocyte and T lymphocyte depleted marrow was studied. Unlike GCT-CM, MO-CM and PHA-LCM stimulated equal proportions of eosinophil progenitors in nondepleted and accessory cell-depleted marrow and demonstrated less hydrocortisone inhibition. However, both GCT-CM and PHA-LCM produced in the presence of hydrocortisone stimulated significantly fewer CFU-Eos in both unfractionated and accessory cell-depleted marrow target populations. These results indicate that the growth of CFU-Eo and inhibition of growth by hydrocortisone is a direct function of a monocyte-T cell interaction and probably is mediated through effects on the production/release of eosinophil colony stimulating factor (Eo-CSF).
D000938:Antigen-Presenting Cells / Q000276:immunology; D001854:Bone Marrow Cells; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D004804:Eosinophils / Q000187:drug effects*; D006098:Granulocytes / Q000145:classification; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D008264:Macrophages / Q000145:classification / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D013234:Stem Cells / Q000187:drug effects*
D003115:Colony-Stimulating Factors; D007375:Interleukin-1; D007376:Interleukin-2; D006854:Hydrocortisone