Lipopolysaccharide-stimulated or granulocyte-macrophage colony-stimulating factor-stimulated monocytes rapidly express biologically active IL-15 on their cell surface independent of new protein synthesis

G. G. Neely, S. M. Robbins, E. K. Amankwah, S. Epelman, H. Wong, J. C.L. Spurrell, K. K. Jandu, W. Zhu, D. K. Fogg, C. B. Brown, C. H. Mody

Research output: Contribution to journalArticlepeer-review

Abstract

Although IL-15 shares many of the biological activities of IL-2, IL-2 expression is primarily under transcriptional regulation, while the mechanisms involved in the regulation of IL-15 are complex and not completely understood. In the current study, we found that CD14+ monocytes constitutively exhibit both IL-15 mRNA and protein. IL-15 protein was found stored intracellularly and stimulation of CD14+ monocytes with either LPS or GM-CSF resulted in mobilization of IL-15 stores to the plasma membrane. This rapidly induced surface expression was the result of a translocation of preformed stores, confirming that posttranslational regulatory stages limit IL-15, because it was not accompanied by an increase in IL-15 mRNA and occurred independent of de novo protein synthesis. After fixation, activated monocytes, but not resting monocytes, were found to support T cell proliferation, and this effect was abrogated by the addition of an IL-15-neutralizing Ab. The presence of preformed IL-15 stores and the ability of stimulated monocytes to mobilize these stores to their surface in an active form is a novel mechanism of regulation for IL-15.

Original languageEnglish (US)
Pages (from-to)5011-5017
Number of pages7
JournalJournal of Immunology
Volume167
Issue number9
DOIs
StatePublished - Nov 1 2001
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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