Interleukin 6 is a permissive factor for monocytic colony formation by human hematopoietic progenitor cells

• Published in: The Journal of experimental medicine Vol. 175; no. 4; pp. 1151 - 1154
• Main Authors: JANSEN, J. H, KLUIN-NELEMANS, J. C, VAN DAMME, J, WIENTJENS, G. J. H. M, WILLEMZE, R, FIBBLE, W. E
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.04.1992; The Rockefeller University Press
• Subjects: Biological and medical sciences; Bone Marrow Cells; Cell physiology; Cells, Cultured; Culture Media, Serum-Free; Fundamental and applied biological sciences. Psychology; Hematopoiesis; Hematopoietic Stem Cells - cytology; Humans; In Vitro Techniques; Interleukin-6 - pharmacology; Molecular and cellular biology; Monocytes - cytology; Receptors, Immunologic - physiology; Receptors, Interleukin-6; Recombinant Proteins; Responses to growth factors, tumor promotors, other factors; Human; Interleukin 6; Cell culture; Monocyte; Hematopoiesis; Cytokine; Hematopoietic cell; Colony; Permissiveness; Cell differentiation; Precursor; Biological activity
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.175.4.1151

Since monocytes and macrophages that arise during the culture of bone marrow progenitor cells are potential sources of interleukin 6 (IL-6), we investigated whether auto- or paracrine production of this factor is involved in colony formation by normal hematopoietic progenitor cells. We added a polyclonal anti-IL-6 antiserum and a monoclonal anti-IL-6 antibody to cultures of monocyte- and T cell-depleted bone marrow cells. Colony formation was stimulated with granulocyte/monocyte-colony-stimulating factor (GM-CSF), monocyte-CSF, or IL-3. Addition of anti-IL-6 antibody resulted in decreased numbers of monocytic colonies to 40-50% of control values, whereas the numbers of granulocytic colonies were not altered. The inhibitory effect was preserved in cultures of CD34(+)-enriched bone marrow cells. As a second approach, we added a monoclonal antibody directed against the IL-6 receptor to cultures of monocyte- and T cell-depleted bone marrow cells. This antibody almost completely inhibited the growth of monocytic colonies, again without decreasing the number of granulocytic colonies. Finally, the importance of IL-6 in monocytopoiesis was demonstrated in serum-deprived bone marrow cultures: addition of exogenous IL-6 to cultures stimulated with GM-CSF resulted in increased numbers of monocytic colonies. Our results indicate that the permissive presence of IL-6 is required for optimal monocytic colony formation by bone marrow progenitor cells.