title: T-cell activation is enhanced by targeting IL-10 cytokine production in toll-like receptor-stimulated macrophages.
abstract: Toll-like receptor (TLR) agonists represent potentially useful cancer vaccine adjuvants in their ability to stimulate antigen-presenting cells (APCs) and subsequently amplify the cytotoxic T-cell response. The purpose of this study was to characterize APC responses to TLR activation and to determine the subsequent effect on lymphocyte activation. We exposed murine primary bone marrow-derived macrophages to increasing concentrations of agonists to TLRs 2, 3, 4, and 9. This resulted in a dose-dependent increase in production of not only tumor necrosis factor-alpha (TNF-α), a surrogate marker of the proinflammatory response, but also interleukin 10 (IL-10), a well-described inhibitory cytokine. Importantly, IL-10 secretion was not induced by low concentrations of TLR agonists that readily produced TNF-α. We subsequently stimulated lymphocytes with anti-CD3 antibody in the presence of media from macrophages activated with higher doses of TLR agonists and observed suppression of interferon gamma release. Use of both IL-10 knockout macrophages and IL-10 small-interfering RNA (siRNA) ablated this suppressive effect. Finally, IL-10 siRNA was successfully used to suppress CpG-induced IL-10 production in vivo. We conclude that TLR-mediated APC stimulation can induce a paradoxical inhibitory effect on T-cell activation mediated by IL-10.
authors.affiliation: Department of Surgery, Walter Reed Army Medical Center, Washington, DC, USA; Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Walk
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Elliott
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Felix C
authors.initials: FC
authors.lastname: Blanco
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Snyder
authors.affiliation: Integrated DNA Technologies, Coralville, IA, USA.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Jacobi
authors.affiliation: Integrated DNA Technologies, Coralville, IA, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Rose
authors.affiliation: Integrated DNA Technologies, Coralville, IA, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Behlke
authors.affiliation: Division of Pharmaceutics, University of Iowa, Iowa City, IA, USA.
authors.forename: Aliasger K
authors.initials: AK
authors.lastname: Salem
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Vukmanovic
authors.affiliation: Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC, USA.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Sandler
keywords: IL-10; innate immunity; toll-like receptors