Granulocyte-macrophage colony-stimulating factor and interleukin-3 mRNAs are produced by a small fraction of blood mononuclear cells

Abstract

Northern blot analysis has identified granulocyte macrophage colony stimulating factor (GM-CSF) mRNA in monocytes and both GM-CSF and interleukin-3 (IL-3) mRNA in lymphocytes. However, these results have not addressed whether all cells or a subset of the population is capable of hematopoietic growth factor (HGF) production. To resolve this question, we applied in situ hybridization of radiolabeled antisense RNA probes to centrifuged preparations of total blood mononuclear cells (BMCs) and fractionated lymphocyte subpopulations. Without stimulation, no circulating cells expressed detectable levels of GM-CSF or IL-3 mRNA. On stimulation of BMCs with phorbol myristate acetate (PMA) and phytohemagglutinin or PMA and the calcium ionophore ionomycin, approximately 5% expressed GM-CSF mRNA and approximately 1% IL-3 mRNA. Control sense probes produced no labeled cells. To determine the subsets of lymphocytes capable of GM-CSF and IL-3 expression, BMCs were fractionated by FACS into CD8+ and CD4+ lymphocyte subsets and CD16+ (NK) cells. The unfractionated cells and cell fractions were then stimulated with PMA and ionomycin. Results demonstrated that 3% to 5% of the CD16+, CD8+, and CD4+ lymphocytes produced GM-CSF mRNA. However, the number of IL-3 mRNA-positive cells in the FACS-sorted subsets was greatly reduced (0.02% to 0.05%) as compared with the unseparated cells (1%). Treatment of BMCs with high-dose interleukin-2 (IL-2) for 1 week followed by PMA plus ionomycin resulted in a lymphocyte population in which 50% and 3% of cells expressed GM-CSF and IL-3 mRNA, respectively. Thus, GM-CSF and IL-3 mRNA expression in T cells and NK cells is restricted to a small fraction of cells that can be greatly expanded by IL-2 stimulation. These results suggest a possible physiologic mechanism for increasing HGF production by circulating lymphocytes.

Granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and granulocyte colony‐stimulating factor (G‐CSF) secretion by adherent monocytes measured by quantitative immunoassays

“…LPS and IL-1 did not induce any GM-CSF secretion and the most effective stimuli were PHA and SEA, which did not stimulate adherent monocytes. Both agents are known to induce multiple cytokine production from T lymphocytes (9,20,24,(33)(34)(35). As expected, GM-CSF but not G-CSF was secreted at a rate much slower than by adherent monocytes and in a time fashion that correlated with cell proliferation.…”

Inhomogeneity of the circulating BFU‐E regulation in sickle cell anaemia: accessory cells properties and BFU‐E growth factor response pattern

“…We report here that GM-CSF is at least one of the factor(sj constitutively released by monocytes of LFSS patients involved in the regulation of circulating BFIJ-E. This is a novel situation, since until now, GM-CSF secretion has not been detected in unstimulated adult accessory cells (Wimperis et al, 1989), except in one instance in which proliferation ofhighly purified progenitors was assayed in culture (Mulligan et al, 1989).…”

Role of Novel Biomarkers of Inflammation in Patients With Stable Coronary Heart Disease

“…It also modulates the activity of these mature cells. 26 IL-3 is produced predominantly by subfractions of CD4 + and CD8 + T lymphocytes undergoing antigenic or mitogenic stimulation 26,27 and by activated mast cells. 28,29 Brizzi et al 30 have shown that IL-3 activates gene transcription of E selectin on endothelial cells and stimulates neutrophil and CD4 + T-cell adhesion to endothelial cells.…”