Interleukin-4 suppresses granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor levels in stimulated human monocytes

Abstract

Granulocyte colony-stimulating factor (G-CSF) was quantitated in the supernatants of lipopolysaccharide (LPS)-treated human monocytes by ELISA. Unlike previous reports, the lymphokines, interleukin-4 (IL-4) and interferon-γ (IFN-γ), were unable to induce the synthesis of G-CSF. Both IL-4 (≥10 pM) and the glucocorticoid, dexamethasone (10-7 M), inhibited G-CSF production in the LPS-treated monocytes; in contrast, IFN-γ had a weak potentiating effect on the LPS action. Changes in antigen expression were manifested at the level of messenger RNA (mRNA). Granulocyte-macrophage (GM)-CSF in the LPS-treated monocyte supernatants was also quantitated by ELISA but its levels were somewhat lower than f..