Cytokines active on granulomonopoiesis: Release and consumption by human marrow myeloid stromal cells

Abstract

Haemopoiesis is sustained and preferentially committed to granulomonopoiesis by myeloid stromal cells generated by colony-derived cell lines (CDCL). Using ELISA and RIA, we studied, in the supernatant of cells from CDCL, the time course of interleukins 3 and 6 (IL-3, IL-6), stem cell factor (SCF), granulocyte-macrophage, granulocyte and macrophage colony stimulating factors (GM-CSF, G-CSF and M-CSF), macrophage-inflammatory protein-1α (MIP-1α) and transforming growth factor β1 (TGF β1). IL-6, GM- CSF, M-CSF and MIP-1α were released into the supernatant after medium renewal and, except for M-CSE addition of iL-1β. G-CSF was detected only after addition of IL-1β. SCF, contained in medium, first declined and then increased 24 h after medium renewal. Release of TGF β1 started 24 h after medium renewal and lasted until day 7. IL-3, provided by horse serum, declined throughout the 7d of observation. In conclusion, stromal cells from CDCL synthesized and released into the supernatant. IL-6, GM-CSF, G-CSF, M- CSF and MIP-1α after stimulation by seric factor(s) and/or IL-1β. TGF β1 was synthesized and released without any obvious extraneous stimuli. There is no definite argument for synthesis of soluble SCF and IL-3. These data support a model where growth factors increase shortly after medium renewal, and negative regulators take over at a later time.