title: Adenovirus type 5 with modified hexons induces robust transgene-specific immune responses in mice with pre-existing immunity against adenovirus type 5.
abstract: BACKGROUND
  Adenovirus type 5 (Ad5) is widely used as a vehicle for vaccine delivery in the treatment of infectious disease and cancer. However, the efficacy of Ad5 vectors has been limited in humans because exposure to Ad5 infections results in most adults having neutralizing antibodies against Ad5. To overcome this limitation, the hexon epitope present in the fifth hypervariable region of Ad5 was modified.
  
  
  METHODS
  To evaluate the ability of Ad5 vectors encoding the HIV env protein to induce Ag-specific immune responses in the face of pre-existing anti-Ad5 immunity, mice were administrated intramuscularly with the Ad-Luc vector, and then vaccinated with parental or hexon-modified Ad5 vectors (Ad-HisHIV, Ad-END/AAAHIV or Ad-HIV) at week 8. HIV-specific cell-mediated immune responses were detected through a combination of tetramer assays and intracellular cytokine staining from weeks 8-23.
  
  
  RESULTS
  The hexon-modified Ad vector was able to escape from anti-Ad5 neutralizing antibody, and mice with the modified vector generated significantly lower individual neutralizing antibody than those immunized with the parental vector. Furthermore, mice with pre-existing anti-Ad immunity immunized with the modified vector generated significantly stronger cell-mediated anti-env responses than those immunized with the parental vector.
  
  
  CONCLUSIONS
  These data demonstrate that Ad5 vector with hexon modification reduce their sensitivity to pre-existing anti-Ad immunity and improve their clinical utility.
authors.affiliation: Department of Molecular Biodefense Research, Yokohama City University Graduate School of Medicine, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Abe
authors.forename: Kenji
authors.initials: K
authors.lastname: Okuda
authors.forename: Takehiro
authors.initials: T
authors.lastname: Ura
authors.forename: Asami
authors.initials: A
authors.lastname: Kondo
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
authors.forename: Shinji
authors.initials: S
authors.lastname: Yoshizaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mizuguchi
authors.forename: Dennis
authors.initials: D
authors.lastname: Klinman
authors.forename: Masaru
authors.initials: M
authors.lastname: Shimada
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000276:immunology; D000818:Animals; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D005260:Female; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007109:Immunity / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D019076:Transgenes
chemical_list: D016207:Cytokines