The capacity to induce cross-presentation dictates the success of a TLR7 agonist-conjugate vaccine for eliciting cellular immunity

J Immunol. 2010 Oct 15;185(8):4602-8. doi: 10.4049/jimmunol.1001892. Epub 2010 Sep 15.

Abstract

Covalent conjugation of TLR agonists to protein Ags often facilitates the generation of a CD8(+) T cell response. However, mechanisms underlying the efficacy of the conjugate over its unconjugated counterpart have been largely uninvestigated. In this study, we show that conjugation of a TLR7 agonist enhances CD8(+) T cell responses without affecting Ag persistence and with minimal impact on cellular uptake of the Ag in vivo. Instead, the conjugated form induced a robust accumulation of dendritic cells (DCs) in regional lymph nodes. Perhaps more importantly, cross-presentation in DCs was detected only when the Ag was delivered in the conjugated form with the TLR7 agonist. Collectively, these data represent the first demonstration that a TLR agonist-Ag conjugate elicits CD8(+) T cell responses based not on its capacity to induce DC maturation or Ag persistence and uptake, but on the engagement of DC cross-presentation pathways.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antigens / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cross-Priming / immunology*
  • Dendritic Cells / immunology
  • Membrane Glycoproteins / agonists*
  • Mice
  • Mice, Inbred C57BL
  • Ovalbumin / immunology
  • Toll-Like Receptor 7 / agonists*
  • Vaccines, Conjugate / immunology*

Substances

  • Antigens
  • Membrane Glycoproteins
  • Tlr7 protein, mouse
  • Toll-Like Receptor 7
  • Vaccines, Conjugate
  • Ovalbumin