title: High-capacity adenoviral vectors circumvent the limitations of ΔE1 and ΔE1/ΔE3 adenovirus vectors to induce multispecific transgene product-directed CD8 T-cell responses.
abstract: BACKGROUND
  The ability to induce cytotoxic T lymphocyte (CTL) responses that are multispecific is considered to comprise an essential feature for an efficacious genetic vaccine against many pathogens including HIV and hepatitis C virus. ΔE1Ad vectors are promising vectored vaccines but have been shown to induce antigen-specific CTLs with only limited multispecificity. In the present study, we investigated the applicability of gene-deleted high-capacity adenovirus (HC-Ad) vectors and focused on the induction of multispecific CTL responses.
  
  
  METHODS
  We generated Δ E1 and HC-Ad vectors expressing hepatitis B virus small surface antigen (HBsAg). We comparatively analyzed the CTL profiles against various transgene product- and vector-derived epitopes in several mouse strains and HBsAg- and vector-directed antibody responses.
  
  
  RESULTS
  HC-Ad vectors efficiently induced multispecific HBsAg-directed CTLs. By contrast, ΔE1Ad vectors mainly primed CTLs against one immunodominant epitope of HBsAg. This absence of multispecific CTL responses correlated with the induction of CTLs against viral epitopes generated by de novo expression of Ad genes from the ΔE1Ad vector. However, Ad-specific CTLs induced in trans did not impair HC-AdS-induced multispecific CTL responses against HBsAg. Finally, HC-Ad vectors also induced higher HBsAg antibody titers compared to ΔE1Ad vectors.
  
  
  CONCLUSIONS
  De novo expression of viral genes from ΔE1Ad vector genomes restricts the multispecificity of transgene product-specific CTLs by immunodominance effects. HC-Ad vectors devoid of Ad genes are favorable for the induction of both multispecific CD8 T-cell responses and high antibody responses. Our results suggest the deletion of Ad genes as an important means for developing potent Ad-based vectored vaccines.
authors.affiliation: Department of Gene Therapy, University of Ulm, Ulm, Germany.
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Kron
authors.forename: Tatjana
authors.initials: T
authors.lastname: Engler
authors.forename: Erika
authors.initials: E
authors.lastname: Schmidt
authors.forename: Reinhold
authors.initials: R
authors.lastname: Schirmbeck
authors.forename: Stefan
authors.initials: S
authors.lastname: Kochanek
authors.forename: Florian
authors.initials: F
authors.lastname: Kreppel
mesh_terms: D062705:Adenovirus Vaccines / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D000818:Animals; D000918:Antibody Specificity / Q000235:genetics / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D017353:Gene Deletion; D005822:Genetic Vectors; D006509:Hepatitis B / Q000235:genetics / Q000276:immunology / Q000628:therapy; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D019076:Transgenes / Q000235:genetics / Q000276:immunology
chemical_list: D062705:Adenovirus Vaccines; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines