title: Improved dendritic cell-based immunization against hepatitis C virus using peptide inhibitors of interleukin 10.
abstract: The high levels of interleukin 10 (IL-10) present in chronic hepatitis C virus (HCV) infection have been suggested as responsible for the poor antiviral cellular immune responses found in these patients. To overcome the immunosuppressive effect of IL-10 on antigen-presenting cells such as dendritic cells (DCs), we developed peptide inhibitors of IL-10 to restore DC functions and concomitantly induce efficient antiviral immune responses. Two IL-10-binding peptides (p9 and p13) were selected using a phage-displayed library and their capacity to inhibit IL-10 was assessed in a bioassay and in STAT-3 (signal transducer and activator of transcription 3) phosphorylation experiments in vitro. In cultures of human leukocytes where HCV core protein induces the production of IL-10, p13 restored the ability of plasmacytoid DC to produce interferon alpha (IFN-α) after Toll-like receptor 9 (TLR9) stimulation. Similarly, when myeloid DCs were stimulated with CD40L in the presence of HCV core, p9 enhanced IL-12 production by inhibiting HCV core-induced as well as CD40L-induced IL-10. Moreover, in vitro, p13 potentiated the effect of maturation stimuli on human and murine DC, increasing their IL-12 production and stimulatory activity, which resulted in enhanced proliferation and IFN-γ production by responding T-cells. Finally, immunization with p13-treated murine DC induced stronger anti-HCV T-cell responses not only in wildtype mice but also in HCV transgenic mice and in mice transiently expressing HCV core in the liver.
  
  
  CONCLUSIONS
  These results suggest that IL-10 inhibiting peptides may have important applications to enhance anti-HCV immune responses by restoring the immunostimulatory capabilities of DC.
authors.affiliation: Division of Hepatology and Gene Therapy, Center for Applied Medical Research, University of Navarra, Pamplona, Spain.
authors.forename: Nancy
authors.initials: N
authors.lastname: Díaz-Valdés
authors.forename: Lorea
authors.initials: L
authors.lastname: Manterola
authors.forename: Virginia
authors.initials: V
authors.lastname: Belsúe
authors.forename: José I
authors.initials: JI
authors.lastname: Riezu-Boj
authors.forename: Esther
authors.initials: E
authors.lastname: Larrea
authors.forename: Itziar
authors.initials: I
authors.lastname: Echeverria
authors.forename: Diana
authors.initials: D
authors.lastname: Llópiz
authors.forename: Jacinto
authors.initials: J
authors.lastname: López-Sagaseta
authors.forename: Hervé
authors.initials: H
authors.lastname: Lerat
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Pawlotsky
authors.forename: Jesús
authors.initials: J
authors.lastname: Prieto
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Lasarte
authors.forename: Francisco
authors.initials: F
authors.lastname: Borrás-Cuesta
authors.forename: Pablo
authors.initials: P
authors.lastname: Sarobe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023201:CD40 Ligand / Q000494:pharmacology; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D016174:Hepacivirus / Q000276:immunology*; D018936:Hepatitis C Antigens / Q000494:pharmacology; D006801:Humans; D016898:Interferon-alpha / Q000096:biosynthesis; D016753:Interleukin-10 / Q000037:antagonists & inhibitors* / Q000276:immunology; D018664:Interleukin-12 / Q000096:biosynthesis*; D051379:Mice; D019151:Peptide Library; D050796:STAT3 Transcription Factor / Q000378:metabolism; D051217:Toll-Like Receptor 9 / Q000502:physiology; D014758:Viral Core Proteins / Q000494:pharmacology
chemical_list: D018936:Hepatitis C Antigens; D016898:Interferon-alpha; D019151:Peptide Library; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D051217:Toll-Like Receptor 9; D014758:Viral Core Proteins; C556202:core protein p13, Hepatitis C virus; C556201:core protein p9, Hepatitis C virus; D016753:Interleukin-10; D023201:CD40 Ligand; D018664:Interleukin-12