Antigen delivery to dendritic cells shapes human CD4+ and CD8+ T cell memory responses to Staphylococcus aureus

PLoS Pathog. 2017 May 25;13(5):e1006387. doi: 10.1371/journal.ppat.1006387. eCollection 2017 May.

Abstract

Intracellular persistence of Staphylococcus aureus favors bacterial spread and chronic infections. Here, we provide evidence for the existence of human CD4+ and CD8+ T cell memory against staphylococcal antigens. Notably, the latter could provide a missing link in our understanding of immune control of intracellular S. aureus. The analyses showed that pulsing of monocyte-derived dendritic cells (MoDC) with native staphylococcal protein antigens induced release of Th2-associated cytokines and mediators linked to T regulatory cell development (G-CSF, IL-2 and IL-10) from both CD4+ and CD8+ T cells, thus revealing a state of tolerance predominantly arising from preformed memory T cells. Furthermore, G-CSF was identified as a suppressor of CD8+ T cell-derived IFNγ secretion, thus confirming a tolerogenic role of this cytokine in the regulation of T cell responses to S. aureus. Nevertheless, delivery of in vitro transcribed mRNA-encoded staphylococcal antigens triggered Th1-biased responses, e.g. IFNγ and TNF release from both naïve and memory T cells. Collectively, our data highlight the potential of mRNA-adjuvanted antigen presentation to enable inflammatory responses, thus overriding the existing Th2/Treg-biased memory T cell response to native S. aureus antigens.

MeSH terms

  • Antigen Presentation
  • Antigens, Bacterial / immunology*
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cytokines / immunology
  • Dendritic Cells / immunology*
  • Granulocyte Colony-Stimulating Factor / immunology
  • Humans
  • Immune Tolerance
  • Interleukin-10 / immunology
  • Interleukin-2 / immunology
  • Staphylococcal Infections / immunology*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / immunology*
  • T-Lymphocytes, Regulatory / immunology
  • Th2 Cells / immunology

Substances

  • Antigens, Bacterial
  • Cytokines
  • IL10 protein, human
  • Interleukin-2
  • Interleukin-10
  • Granulocyte Colony-Stimulating Factor

Grants and funding

The work was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft grant #BE3841/2-1 to IBD, #504/10-1 to GB and GO 371/9-1 and TRR34 to FG). The funding institution had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.