title: Adenovirus efficiently transduces plasmacytoid dendritic cells resulting in TLR9-dependent maturation and IFN-alpha production.
abstract: BACKGROUND
  Recombinant replication-deficient adenoviral vectors (recAd) are attractive candidates for DNA vaccination approaches because they are able to activate the innate and adaptive immune systems. Here we explore the ability of recAd to transduce and activate subsets of dendritic cells, namely plasmacytoid dendritic cells (pDC) and conventional dendritic cells (cDC).
  
  
  METHODS
  DC were derived from bone marrow precursors in vitro with the help of FLT3-ligand. Sorted populations of pDC and cDC were infected with recAd at various multiplicities of infection. Transduction efficiency, phenotypic maturation and production of IFN-alpha as well as IL-6 were assessed. Additionally, activation of DC and induction of cytotoxic T lymphocytes (CTL) were determined in vivo. The role of Toll-like receptor (TLR) 9 in recAd recognition was investigated as it has previously been shown that DNA viruses are recognized via this receptor.
  
  
  RESULTS
  RecAd can efficiently transduce pDC as well as cDC in vitro. Both DC subsets mature and produce IFN-alpha upon interaction with recAd. In the absence of TLR9, activation and cytokine production was only detected in cDC but not in pDC. Importantly, induction of CD8+ CTL following in vivo injection of recAd was similar in TRL9-deficient mice when compared with wildtype controls.
  
  
  CONCLUSIONS
  RecAd can efficiently transduce and activate both pDC and cDC. pDC required TLR9 to detect the presence of recAd whereas cDC also recognized recAd independently of TLR9. These unique immunostimulatory properties support the future development of recombinant Ad as a vector for DNA vaccine approaches.
authors.affiliation: Laboratory of Experimental Dermatology, Department of Dermatology, University of Bonn, Germany.
authors.forename: Etiena
authors.initials: E
authors.lastname: Basner-Tschakarjan
authors.forename: Evelyn
authors.initials: E
authors.lastname: Gaffal
authors.forename: Meredith
authors.initials: M
authors.lastname: O'Keeffe
authors.forename: Damia
authors.initials: D
authors.lastname: Tormo
authors.forename: Andreas
authors.initials: A
authors.lastname: Limmer
authors.forename: Hermann
authors.initials: H
authors.lastname: Wagner
authors.forename: Hubertus
authors.initials: H
authors.lastname: Hochrein
authors.forename: Thomas
authors.initials: T
authors.lastname: Tüting
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000276:immunology*; D000818:Animals; D002454:Cell Differentiation; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D051217:Toll-Like Receptor 9 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014161:Transduction, Genetic
chemical_list: C408982:CPG-oligonucleotide; D016898:Interferon-alpha; D009838:Oligodeoxyribonucleotides; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9