IL-10-inducing adjuvants enhance sublingual immunotherapy efficacy in a murine asthma model

Int Arch Allergy Immunol. 2008;145(2):152-62. doi: 10.1159/000108140. Epub 2007 Sep 11.

Abstract

Background: IL-10-inducing adjuvants could enhance the efficacy of allergy vaccines in establishing allergen-specific tolerance. The aim of this study was to identify such adjuvants using in vitro cultures of human and murine cells and to evaluate them in a therapeutic murine model of sublingual immunotherapy (SLIT).

Methods: Adjuvants stimulating IL-10 gene expression by human or murine immune cells were tested sublingually in BALB/c mice sensitized to ovalbumin (OVA), assessing the reduction in airway hyperresponsiveness (AHR) by whole-body plethysmography. The induction of regulatory T cells (T(reg)) was evaluated using phenotypic and functional assays. T-cell proliferation in cervical lymph nodes (LNs) was assessed following intravenous transfer of CFSE-labelled OVA-specific T cells and FACS analysis.

Results: A combination of 1,25-dihydroxyvitamin D3 plus dexamethasone (VitD3/Dex) as well as Lactobacillus plantarum were found to induce IL-10 production by human and murine dendritic cells (DCs). The former inhibits LPS-induced DC maturation, whereas L. plantarum induces DC maturation. Following stimulation with VitD3/Dex-pretreated DCs, CD4+ naïve T cells exhibit a T(reg) profile. In contrast, a Th1/T(reg) pattern of differentiation is observed in the presence of DCs treated with L. plantarum. Both adjuvants significantly enhance SLIT efficacy in mice, in association with either induction of Foxp3+ T(reg) cells (for VitD3/Dex) or proliferation of OVA-specific T cells in cervical LNs (for L. plantarum).

Conclusions: Both VitD3/Dex and L. plantarum polarize naïve T cells towards IL-10-expressing T cells, through distinct mechanisms. As adjuvants, they both enhance SLIT efficacy in a murine asthma model.

MeSH terms

  • Adjuvants, Immunologic / pharmacology*
  • Administration, Sublingual
  • Animals
  • Asthma / therapy*
  • Calcitriol / administration & dosage
  • Calcitriol / pharmacology*
  • Cells, Cultured / drug effects
  • Cells, Cultured / immunology
  • Dendritic Cells / drug effects*
  • Dendritic Cells / immunology
  • Desensitization, Immunologic*
  • Dexamethasone / administration & dosage
  • Dexamethasone / pharmacology*
  • Drug Evaluation, Preclinical
  • Female
  • Humans
  • Interleukin-10 / biosynthesis*
  • Interleukin-10 / genetics
  • Lactobacillus plantarum / immunology*
  • Lactobacillus rhamnosus / immunology
  • Lymph Nodes / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Transgenic
  • Ovalbumin / toxicity
  • T-Lymphocyte Subsets / drug effects
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes, Regulatory / drug effects*
  • T-Lymphocytes, Regulatory / immunology

Substances

  • Adjuvants, Immunologic
  • Interleukin-10
  • Dexamethasone
  • Ovalbumin
  • Calcitriol