A composite MyD88/CD40 switch synergistically activates mouse and human dendritic cells for enhanced antitumor efficacy

J Clin Invest. 2011 Apr;121(4):1524-34. doi: 10.1172/JCI44327. Epub 2011 Mar 7.

Abstract

The in vivo therapeutic efficacy of DC-based cancer vaccines is limited by suboptimal DC maturation protocols. Although delivery of TLR adjuvants systemically boosts DC-based cancer vaccine efficacy, it could also increase toxicity. Here, we have engineered a drug-inducible, composite activation receptor for DCs (referred to herein as DC-CAR) comprising the TLR adaptor MyD88, the CD40 cytoplasmic region, and 2 ligand-binding FKBP12 domains. Administration of a lipid-permeant dimerizing ligand (AP1903) induced oligomerization and activation of this fusion protein, which we termed iMyD88/CD40. AP1903 administration to vaccinated mice enabled prolonged and targeted activation of iMyD88/CD40-modified DCs. Compared with conventionally matured DCs, AP1903-activated iMyD88/CD40-DCs had increased activation of proinflammatory MAPKs. AP1903-activated iMyD88/CD40-transduced human or mouse DCs also produced higher levels of Th1 cytokines, showed improved migration in vivo, and enhanced both antigen-specific CD8+ T cell responses and innate NK cell responses. Furthermore, treatment with AP1903 in vaccinated mice led to robust antitumor immunity against preestablished E.G7-OVA lymphomas and aggressive B16.F10 tumors. Thus, the iMyD88/CD40 unified "switch" effectively and safely replaced exogenous adjuvant cocktails, allowing remote and sustained DC activation in vivo. DC "licensing" through iMyD88/CD40 may represent a mechanism by which to exploit the natural synergy between the TLR and CD40 signaling pathways in DCs using a single small molecule drug and could augment the efficacy of antitumor DC-based vaccines.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / administration & dosage
  • Animals
  • CD40 Antigens / administration & dosage*
  • CD40 Antigens / genetics
  • CD40 Antigens / immunology
  • Cancer Vaccines / administration & dosage*
  • Cancer Vaccines / genetics
  • Cancer Vaccines / immunology
  • Dendritic Cells / immunology*
  • Drug Synergism
  • Female
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myeloid Differentiation Factor 88 / administration & dosage*
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / immunology
  • NF-kappa B / metabolism
  • Neoplasms, Experimental / immunology
  • Neoplasms, Experimental / therapy
  • Organic Chemicals / administration & dosage
  • Protein Engineering
  • Tacrolimus Binding Protein 1A / genetics
  • Tacrolimus Binding Protein 1A / immunology
  • Toll-Like Receptors / immunology

Substances

  • Adjuvants, Immunologic
  • CD40 Antigens
  • Cancer Vaccines
  • MYD88 protein, human
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • NF-kappa B
  • Organic Chemicals
  • Toll-Like Receptors
  • Tacrolimus Binding Protein 1A
  • AP 1903 reagent