Retinal pigment epithelial cells secrete interleukin-6 in response to interleukin-1

• Published in: Investigative ophthalmology & visual science Vol. 33; no. 1; pp. 78 - 82
• Main Authors: Planck, SR, Dang, TT, Graves, D, Tara, D, Ansel, JC, Rosenbaum, JT
• Format: Journal Article
• Language: English
• Published: Rockville, MD ARVO 01.01.1992; Association for Research in Vision and Ophtalmology
• Subjects: Biological and medical sciences; Blotting, Northern; Blotting, Western; Cell Division; Cell physiology; Cells, Cultured; DNA Probes; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Humans; Interleukin-1 - pharmacology; Interleukin-6 - secretion; Molecular and cellular biology; Pigment Epithelium of Eye - cytology; Pigment Epithelium of Eye - immunology; RNA - analysis; Vision, photoreception; Human; Interleukin 6; Synthesis; Tissue culture; Pigment epithelium; Epithelial cell; Exploration; Retina; In vitro
• ISSN: 0146-0404; 1552-5783

Interleukin-6 (IL-6) is a peptide whose properties include the ability to activate T-lymphocytes, stimulate the secretion of immunoglobulin, induce neuronal differentiation, and trigger the release of acute phase proteins. We have detected IL-6-like activity in conditioned medium from cultured human retinal pigment epithelial (RPE) cells with a bioassay based on the ability of IL-6 to induce the proliferation of murine B-9 plasmacytoma cells. Biologic activity increased approximately 90-fold when the cells were cultured in the presence of IL-1 alpha (30 units/ml). Western blot analysis confirmed that conditioned medium from IL-1 alpha-stimulated RPE cells contained peptides with molecular weights ranging between 19,000 and 30,000 and reactive with antibody to IL-6. Finally, Northern blot analysis indicated that cells cultured in the presence of interleukin-1 contained a 1.2 kilobase transcript that hybridized to a cDNA probe specific for IL-6 messenger RNA. IL-6 peptide on Western blots and mRNA on Northern blots were undetectable unless cells were cultured in the presence of IL-1 alpha. Although IL-6 is synthesized by a variety of cell types, this report is the first to detect its synthesis by an eye-specific cell type. Furthermore, these observations indicate that retinal pigment epithelial cells respond to IL-1, a cytokine that previously has been implicated in ocular inflammation.